Repository: Artoria2e5/PRCoords
Branch: master
Commit: a853b1fc19ee
Files: 51
Total size: 138.8 KB
Directory structure:
gitextract_j7s_ktue/
├── .gitignore
├── .npmignore
├── .vscode/
│ └── settings.json
├── LICENSE.gplv3
├── README.md
├── approx/
│ └── approx.ipynb
├── cpp/
│ ├── Makefile
│ ├── badmath.hh
│ ├── bench.cc
│ ├── bench4.sh
│ ├── bench_out/
│ │ ├── README.md
│ │ ├── native_nick.md
│ │ ├── native_stdsin.md
│ │ ├── nick.md
│ │ └── stdsin.md
│ ├── demo.cc
│ ├── libprcoords.cc
│ └── prcoords.h
├── docs/
│ ├── demo.html
│ ├── index.md
│ └── proj4_plugin.js
├── haskell/
│ ├── PRCoords.cabal
│ ├── PRCoords.hs
│ └── Setup.hs
├── js/
│ ├── .npmignore
│ ├── PRCoords.d.ts
│ ├── PRCoords.js
│ ├── misc/
│ │ ├── insane_is_in_china.js
│ │ └── package.json
│ └── package.json
├── julia/
│ ├── Project.toml
│ └── src/
│ └── PRCoords.jl
├── lua/
│ └── PRCoords.lua
├── matlab/
│ ├── PRCoords.m
│ ├── bd_gcj.m
│ ├── bd_gcj_precise.m
│ ├── bd_wgs.m
│ ├── bd_wgs_precise.m
│ ├── caijun_precise.m
│ ├── gcj_bd.m
│ ├── gcj_wgs.m
│ ├── gcj_wgs_precise.m
│ ├── wgs_bd.m
│ └── wgs_gcj.m
├── package.json
├── pgsql/
│ ├── distance_agg.sql
│ ├── prcoords.sql
│ └── prcoords_postgis.sql
├── py/
│ ├── prcoords.py
│ └── setup.py
└── racket/
└── prcoords.rkt
================================================
FILE CONTENTS
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================================================
FILE: .gitignore
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py/*/
cpp/*.exe
cpp/*.a
cpp/*.dll
cpp/*.so
cpp/*.o
cpp/*.obj
cpp/*.def
cpp/*.lib
cpp/*.exp
node_modules
julia/.vscode/settings.json
cpp/nanobench.h
cpp/bench
cpp/demo
================================================
FILE: .npmignore
================================================
# npm sucks and i can only put things under git root
/*
!/js
js/misc
!/doc
================================================
FILE: .vscode/settings.json
================================================
{
"files.associations": {
"*.embeddedhtml": "html",
"iostream": "cpp"
}
}
================================================
FILE: LICENSE.gplv3
================================================
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GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES.
17. Interpretation of Sections 15 and 16.
If the disclaimer of warranty and limitation of liability provided
above cannot be given local legal effect according to their terms,
reviewing courts shall apply local law that most closely approximates
an absolute waiver of all civil liability in connection with the
Program, unless a warranty or assumption of liability accompanies a
copy of the Program in return for a fee.
END OF TERMS AND CONDITIONS
How to Apply These Terms to Your New Programs
If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.
To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
state the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.
{one line to give the program's name and a brief idea of what it does.}
Copyright (C) {year} {name of author}
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
Also add information on how to contact you by electronic and paper mail.
If the program does terminal interaction, make it output a short
notice like this when it starts in an interactive mode:
{project} Copyright (C) {year} {fullname}
This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License. Of course, your program's commands
might be different; for a GUI interface, you would use an "about box".
You should also get your employer (if you work as a programmer) or school,
if any, to sign a "copyright disclaimer" for the program, if necessary.
For more information on this, and how to apply and follow the GNU GPL, see
<http://www.gnu.org/licenses/>.
The GNU General Public License does not permit incorporating your program
into proprietary programs. If your program is a subroutine library, you
may consider it more useful to permit linking proprietary applications with
the library. If this is what you want to do, use the GNU Lesser General
Public License instead of this License. But first, please read
<http://www.gnu.org/philosophy/why-not-lgpl.html>.
================================================
FILE: README.md
================================================
PRCoords
========
People's Rectified Coordinates (PRCoords) is a cross-language implementation of "public secret" Chinese coordinate obfuscation methods including GCJ-02 and BD-09, along with general deobfuscation methods previously established in [ChinaMapShift][], [eviltransform][], and [geoChina][]. (Referring to the process of replacing straight lines with wavy ones as a "transform" is euphemism overdone.)
For a background on China's geographic obfuscation, see [Restrictions on geographic data in China](https://en.wikipedia.org/wiki/Restrictions_on_geographic_data_in_China#Coordinate_systems) and [中华人民共和国测绘限制](https://zh.wikipedia.org/wiki/中华人民共和国测绘限制) on Wikipedia.
[ChinaMapShift]: https://gist.github.com/anonymous/e7c6f67555099180ce1ae8da4ba2c513
[geoChina]: https://github.com/caijun/geoChina/blob/master/R/cst.R
[eviltransform]: https://github.com/googollee/eviltransform
Languages
---------
- [x] JavaScript ([`npm install prcoords`](https://www.npmjs.com/package/prcoords)) [](https://www.jsdelivr.com/package/npm/prcoords)
* Web demo: https://artoria2e5.github.io/PRCoords/demo
* Now with AMD support and faux `__esModule` interop for Babel and TypeScript!
- [x] Python ([`pip install prcoords`](https://pypi.org/project/prcoords/))
- [x] \(Obj-\)C/C++ (C ABI)
* [x] Makefile with `install`
- [ ] Ruby
- [ ] Swift
- [ ] C#
- [x] Haskell (GCJ only; data structure incomplete)
* need to move googollee/eviltransform#54 here sometime.
- [ ] Java
- [x] Matlab/Octave
- [x] PGSQL
- [ ] Typed Racket
* is it done?
(should I split them into submodules?)
For languages not yet supported, we recommend you to check for [eviltransform][] (MIT) or [geoChina][] (GPLv3, R) instead.
API
---
PRCoord's APIs operate on, and returns, dedicated structures for coordinates. In API names, we generally refer to WGS-84 as `wgs`, GCJ-02 as `gcj`, and BD-09 (lat-lon) as `bd`.
### Inverse functions
The obfuscations generally have these properties to maintain basic usefulness:
1. `obfs(coord)` is sort of close to `coord`.
2. `obfs(a) - obfs(b)` is usually close to `a - b`. (The closer `a` and `b` are
to each other, the better it works.)
In general two approaches of inverting the "forward" obfuscations, or working from
`obfs(coord)` to `coord`, are implemented:
* _Run it backwards_: `obfs(coord)` is never too far from `coord`, so just use
`obfs(obfs(coord)) - obfs(coord)` to estimate `obfs(coord) - coord`.
* _Iterate a bit_: Get a rough `guess` somehow, and just use property 2 to estimate
the remaining error as `obfs(guess) - obfs(coord)` and correct the `guess`.
You can read on the demo page about how well these methods work from the `ΔRoundtrip`
entry. Unless you are doing archival work, you generally don't have to iterate.
### The "in China" sanity check
Typically PRCoords is only supposed to be ran on obfuscated input data, which
are primarily Chinese coordinates. For this reason, initial implementations
include this [very very rough](https://news.ycombinator.com/item?id=10965506)
sanity check that spans a rectangular region on a mercator-projected map.
This check can be overridden by passing a boolean value, or may be not at all
implemented in certain languages if I am not in the right mood for doing
silly things.
There is an "insane" sanity check intended to approximate the range of Google
and Baidu's distortion, intended for use by [IITC](https://iitc.me):
[`js/insane_is_in_china.js`](https://github.com/Artoria2e5/PRCoords/blob/master/js/insane_is_in_china.js).
It is basically a ray-casting polygon check with 70 vertices. You, as the
caller, should still be responsible for telling whether a point is part of the
gov-screwed Chinese data.
FAQ
---
### Why another wheel?
* Correctness
* Public Domain
* Clean API based on pairs of coordinates
* Need to find a place for this sarcastic name
### Can the systems be described as WKT or proj-strings?
Not directly as a datum, because in both representations a datum is either
"sane" (no non-linearity in 3D, Helmert possible) or a big table of grids.
It should be possible to describe the two CS with a `PROJECTION` entry as
a `PROJCS`. Since a `PROJCS` cannot be nested in another, the BD
transformation must be described using WGS84 and a fuzed GCJ-BD projection.
The situation is similar with [Baidu "Meractor"](https://github.com/gumblex/cntms/commit/bbde4006adeb92f48da1ff7d1f88da393d382f8a).
<details>
<summary>Speculative WKT/PROJ4</summary>
```js
PROJCS["Baidu 2009, Pseudo-Mercator",
GEOGCS["WGS 84",
DATUM["WGS_1984",
SPHEROID["WGS 84",6378137,298.257223563,
AUTHORITY["EPSG","7030"]],
AUTHORITY["EPSG","6326"]],
PRIMEM["Greenwich",0,
AUTHORITY["EPSG","8901"]],
UNIT["degree",0.0174532925199433,
AUTHORITY["EPSG","9122"]],
AUTHORITY["EPSG","4326"]],
PROJECTION["CN_Obfs_Baidu_2009_Mercator"],
AXIS["x",east],
AXIS["y",north],
UNIT["metre",1,
AUTHORITY["EPSG","9001"]],
EXTENSION["PROJ4","+proj=baidumerc +units=m +nadgrids=@null +wktext +no_defs"],
AUTHORITY["EPSG","888002"]]
PROJCS["Chinese BSM 2002, Pseudo-Ellipsoidal",
GEOGCS["WGS 84", AUTHORITY["EPSG","4326"]],
PROJECTION["CN_Obfs_GCJ_2002_Ellipsoidal"],
AXIS["longitude",east],
AXIS["latitude",north],
UNIT["degree",0.0174532925199433,
AUTHORITY["EPSG","9122"]],
EXTENSION["PROJ4","+proj=gcjlonglat +units=deg +nadgrids=@null +wktext +no_defs"],
AUTHORITY["EPSG","888000"]]
```
</details>
The good people at proj4js has made their stuff [very easy to extend](https://github.com/proj4js/proj4js/issues/358). Here is [an example](https://runkit.com/artoria2e5/proj4-plugin-prcoords) (backed up in [`docs/proj4_plugin.js`](https://github.com/Artoria2e5/PRCoords/blob/master/docs/proj4_plugin.js) in case RunKit goes down) of how to add PRCoords support to proj4js.
### Should I use fast fp math?
Yes. Nobody knows what the original looks like anyways, so what's wrong with letting the compiler recombine a bit more? You can't be more off
than the one-meter random error (in "EMQ") anyways.
Or tinker with 32-bit floats and fixed-point numbers. Or try approximation tools like [Sollya](http://sollya.gforge.inria.fr/) or [MC++](https://omega-icl.github.io/mcpp/). Really, just search on the Internet for "\<language\> Taylor Chebyshev Model". You only need less than 1e-6 error on a [not-very-large slice](https://github.com/Artoria2e5/PRCoords/blob/a3a8bb8/js/PRCoords.js#L91) of the Earth anyways.
I threw TaylorModels.jl at GCJ-02, and got ~~decent~~ results out of it. Still too lazy to put it in code though. Check out [approx/approx.ipynb](https://github.com/Artoria2e5/PRCoords/blob/master/approx/approx.ipynb). (Nope, not decent. Gotta do it properly some day, just don't use the notebook and expect it to work!)
I tried another route with the C++ version using a devmaster user Nick's `sinpi()` approximation. It seems to be good enough for 1e-6: check out [cpp/bench_out](https://github.com/Artoria2e5/PRCoords/tree/master/cpp/bench_out) and [cpp/badmath.hh](https://github.com/Artoria2e5/PRCoords/blob/master/cpp/badmath.hh).
Physical PRCoords
-----------------
You can print out a minimal copy of PRCoords with [this PDF file](https://commons.wikimedia.org/wiki/File:PRcoords_Cheatsheet.pdf). I am working on some better options [in issue #2](https://github.com/Artoria2e5/PRCoords/issues/2). A fairly simple tote bag with an older version of the PDF is [available from Teespring](https://teespring.com/miniprcoords-tote-v1).
Feel free to print and sell t-shirts with the PDF file! It is put in the Public Domain, so you don't have to pay me for that. You can always fund my subversive activities on [Patreon](https://www.patreon.com/artoria2e5) though.
License
-------
Unless otherwise mentioned, all files in this package, including this README file,
are dual-licensed under:
* [CC0 1.0 Public Domain Dedication](https://creativecommons.org/publicdomain/zero/1.0/)
* [GNU General Public License (version 3 or up)](https://gnu.org/licenses/gpl.html)
GPL is only included for fun here.
Sources
-------
* [Algorithm.Coords.Converter](https://archive.is/20130815104734/emq.googlecode.com/svn/emq/src/Algorithm/Coords/Converter.java) from [EMQ](https://code.google.com/archive/p/emq/) ([GitHub mirror](https://github.com/richardyu-au/emq)) is probably *the* GCJ leak. It is a JSP project "for demonstrating GIS systems", probably done by some government contractor.
* There is some randomness in the GCJ deltas on both axes: one `sin` invocation and one LCG. Each add a maximum of 1 meter of error.
* [on4wp7](https://archive.is/20150702191259/https://on4wp7.codeplex.com/SourceControl/changeset/view/21483%23353936) (2013) is the earliest rationalized GCJ (forward) implementation. No randomness is attempted.
* [ChinaMapShift][] (2014) figured out the quick iterative inverse for GCJ. I learned about it via geoChina first and generalized it here.
* BD-09 is not very well sourced, but [pycoordtrans](https://github.com/zxteloiv/pycoordtrans) (2014) seems to have it.
See also
--------
* [eviltransform][] is among the most popular cross-language soltions to the problem. It borrows its name directly from [EvilTransform.cs](https://github.com/Leask/EvilTransform/blob/master/EvilTransform.cs), an early refactored version of a raw-flesh Java implementation found in "[emq](https://code.google.com/archive/p/emq/)", some sort of government contractor GIS demo project.
* Since June 2016, eviltransform contains numerous parameter errors that compromise its output, especially for BD-09. See googollee/eviltransform[#43](https://github.com/googollee/eviltransform/issues/43), [#53](https://github.com/googollee/eviltransform/pull/53) and [#44](https://github.com/googollee/eviltransform/issues/44) for corrections. As of June 2019 these problems are not fixed.
* [geoChina][] by caijun is a clear, concise implementation written in R. It features the iterative method from ChinaMapShift.
* I am planning on moving some of the comments on the algorithm found in [my initial JavaScript implementation](https://zh.wikipedia.org/wiki/User:Artoria2e5/PRCoords.js) to the [GitHub Wiki](https://github.com/Artoria2e5/PRCoords/wiki). I don't think anyone is going to be interested in copying comments on these idiocy when translating my implementation to other languages.
* If you are doing a translation, consider only using the comments from the PDF.
* [Ishisashi's writeup](https://chaoli.club/index.php/4777/0) on this subject. They wrote a super enhanced version of the demo too.
Oh, and finally, here is an official [news report](https://archive.fo/20110804185923/http://cxzy.people.com.cn/GB/196034/14908095.html) on that particular *\[bleep\]* who came up with GCJ-02.
<a href="https://artoria2e5.github.io/PRCoords/demo">
<img src="https://Artoria2e5.github.io/PRCoords/Globe%2C_distorted_China.svg" width="100%" height="100">
</a>
================================================
FILE: approx/approx.ipynb
================================================
{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Approximation\n",
"=============\n",
"\n",
"Scroll down and you should find some approximations of the obfuscation code.\n",
"I have no idea what evil forces compelled me to do this, but eh let's roll with it."
]
},
{
"cell_type": "code",
"execution_count": 3,
"metadata": {},
"outputs": [],
"source": [
"using TaylorModels"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"GCJ-02\n",
"------\n",
"\n",
"The `abs()` makes it impossible to feed into taylor, so I think I will just feed the trigs in. Splitting the x and y too, so we don't get a lot of zero in the coeffs.\n",
"\n",
"Let's start with... typing the formulae:"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {},
"outputs": [
{
"data": {
"text/plain": "e1 (generic function with 1 method)"
},
"execution_count": 4,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"# Not gonna type these pi.\n",
"spi(x) = sin(x * pi)\n",
"\n",
"# Just the core meter-level shite. 1 and 2 are to be fed to taylor.\n",
"n0(x, y) = -100 + 0.1x*y + 0.2 * sqrt(abs(x))\n",
"n1(x) = 2x + 20 / 3 * (2 * spi(6x) + 2 * spi(2x))\n",
"n2(y) = 3y + 0.2y^2 + 20 / 3 * (2 * spi(y) + 4 * spi(y/3) + 16 * spi(y/12) + 32 * spi(y/30))\n",
"\n",
"e0(x, y) = 300 + 0.1x*y + 0.1 * sqrt(abs(x)) + 2y\n",
"e1(x) = x + 0.1x^2 + 20 / 3 * (2 * spi(6x) + 2 * spi(2x) + 2 * spi(x) + 4 * spi(x/3) + 15 * spi(x/12) + 30 * spi(x/30))"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Set up for TaylorModels:"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"n1tm = [337.103, 337.104] t + [-15434.3, -15434.2] t³ + [265489, 265490] t⁵ + [-4.894e+16, 4.894e+16]\n",
"n2tm = [123.078, 123.079] t + [0.2, 0.200001] t² + [-74.3666, -74.3665] t³ + [34.2831, 34.2832] t⁵ + [-1.74906e+11, 1.74906e+11]\n",
"e1tm = [453.04, 453.041] t + [0.1, 0.100001] t² + [-15508.6, -15508.5] t³ + [265523, 265524] t⁵ + [-4.89402e+16, 4.89402e+16]\n"
]
}
],
"source": [
"x_dom = -30..30\r\n",
"y_dom = -30..20\r\n",
"\r\n",
"# 35,105 as the center of China. What can go wrong?\r\n",
"x0 = 0\r\n",
"y0 = 0\r\n",
"\r\n",
"ORDER = 6\r\n",
"\r\n",
"tmx = TaylorModel1(ORDER, interval(x0), x_dom)\r\n",
"tmy = TaylorModel1(ORDER, interval(y0), y_dom)\r\n",
"\r\n",
"n1tm = n1(tmx)\r\n",
"n2tm = n2(tmy)\r\n",
"e1tm = e1(tmx)\r\n",
"\r\n",
"println(\"n1tm = \", n1tm)\r\n",
"println(\"n2tm = \", n2tm)\r\n",
"println(\"e1tm = \", e1tm)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"Oh well, the last term is way better than what I expected. Let's export them as usual polynomials then."
]
},
{
"cell_type": "code",
"execution_count": 6,
"metadata": {},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"n1t = 337.10321638291134 t - 15434.235503082582 t³ + 265489.0776448309 t⁵ + 𝒪(t⁷)\n",
"n2t = 123.07865253720988 t + 0.2 t² - 74.36657685107961 t³ + 34.28315615652991 t⁵ + 𝒪(t⁷)\n",
"e1t = 453.0402762665314 t + 0.1 t² - 15508.57959081323 t³ + 265523.36073126463 t⁵ + 𝒪(t⁷)\n"
]
}
],
"source": [
"function mid_tm(t::TaylorModel1)\r\n",
" coeffs = map(x -> mid(x), t.pol.coeffs)\r\n",
" order = t.pol.order\r\n",
" return Taylor1(coeffs, order)\r\n",
"end\r\n",
"n1t = mid_tm(n1tm)\r\n",
"n2t = mid_tm(n2tm)\r\n",
"e1t = mid_tm(e1tm)\r\n",
"println(\"n1t = \", n1t)\r\n",
"println(\"n2t = \", n2t)\r\n",
"println(\"e1t = \", e1t)"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"These should be good enough to just translate into code. If you are allowing the compiler to reassoc, there should be no need of manually writing Horner and thinking about pipelines. The reduced number of operations might even make `f32` acceptable. I will eventually put it in the cpp thing and check it.\r\n",
"\r\n",
"The arclen stuff have the same `sqrt` issue, so it's not getting changed here.\r\n",
"\r\n",
"Okay, actually, **no**. The range of numbers means that `t^7` is ridiculously large. I should really throw this at MetaLibm-Lutetia\r\n",
"and ask it to do the argument reduction for me...\r\n",
"\r\n",
"BD-09\r\n",
"----\r\n",
"We have a `sqrt` in `hypot`, so no. We can't fuze any operations here anyways.\r\n",
"\r\n",
"\r\n",
"Plotting session\r\n",
"----------------\r\n",
"Oops UI can't install `Plots`. And I just realized the resulting numbers are\r\n",
"unreasonably large. Oops."
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {},
"outputs": [],
"source": []
}
],
"metadata": {
"kernelspec": {
"display_name": "Julia 1.5.0-rc1",
"language": "julia",
"name": "julia-1.5"
},
"language_info": {
"file_extension": ".jl",
"mimetype": "application/julia",
"name": "julia",
"version": "1.5.0"
},
"orig_nbformat": 2
},
"nbformat": 4,
"nbformat_minor": 2
}
================================================
FILE: cpp/Makefile
================================================
CXXFLAGS = -O3 -funsafe-math-optimizations -fno-math-errno -std=c++0x -Wall -Wextra -fvisibility=hidden -fvisibility-inlines-hidden -DNDEBUG $(XCXXFLAGS)
# "Cross compile" shite. In other words MinGW.
# TARGET is Triplet PLUS THE HYPHEN!
CC = $(TARGET)gcc
CXX = $(TARGET)g++
AR ?= $(TARGET)ar
DLLTOOL ?= $(TARGET)dlltool
# for clang's llvm bitcode: CCAR=llvm-ar
CCAR ?= gcc-ar
# Override when using CYGWIN: make [target] LIB=cyg SO=dll
# Override when using MinGW: make [target] LIB='' SO=dll TARGET=x86_64-w64-mingw32-
LIB ?= lib
SO ?= so
# Installation
DESTDIR ?=
PREFIX ?= /usr/local
# Path to the Microsoft Library Manager (LIB.exe)
# Available from https://aka.ms/buildtools
# Tends to be buried deep, e.g. C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.22.27905\bin\Hostx64\x64
# I recommend putting a shell script called lib.exe in /usr/local/bin to call it with "$@"
#
# Mingw-W64 has a genlib.exe for those who dare to try. It generates MSVC-style
# __IMPORT_DESCRIPTOR_%s. Or maybe the ld -Wl,--out-implib will work with MSVC
# too with __imp symbols only, who knows.
#
# Note that this is only meaningful for MinGW output: Cygwin/MSYS builds have
# dependency for cygwin1.dll, which triggers address-clashes with MSVC's libs.
#
# cl /Fe:demo-cl.exe demo.cc prcoords.lib
LIBEXE ?= LIB.exe
# Or /machine:x86.
LIBFLAGS ?= /machine:x64
all: libprcoords.a $(LIB)prcoords.$(SO) demoso
prec_sample: demo demof demold
windows: all $(LIB)prcoords.lib
# We assume that your copy of "ar" supports the "s" option,
# which does some ranlib work itself.
libprcoords.a: libprcoords.o
$(AR) rcs libprcoords.a libprcoords.o
libprcoords-lto.a: libprcoords-lto.o
$(CCAR) rcs libprcoords-lto.a libprcoords-lto.o
$(LIB)prcoords.$(SO): libprcoords.o
$(CC) -shared -o $(LIB)prcoords.$(SO) libprcoords.o
libprcoords.o: libprcoords.cc badmath.hh
$(CC) $(CXXFLAGS) -fPIC -c -DPRCOORDS_DLL -DPRCOORDS_DLL_EXPORTS libprcoords.cc
libprcoords-lto.o: libprcoords.cc
$(CC) $(CXXFLAGS) -flto -ffat-lto-objects -c libprcoords.cc -o libprcoords-lto.o
# Import library generation for MSVC users (optional)
$(LIB)prcoords.def: libprcoords.o
$(DLLTOOL) --dllname $(LIB)prcoords.$(SO) -z $(LIB)prcoords.def --export-all-symbols libprcoords.o
# Also spits out an .exp
$(LIB)prcoords.lib: $(LIB)prcoords.def
$(LIBEXE) $(LIBFLAGS) /nologo /def:$(LIB)prcoords.def /out:$(LIB)prcoords.lib
demo: demo.cc libprcoords.cc
$(CXX) $(CXXFLAGS) -DPRCOORDS_DEMO_FORCE_STANDALONE=1 -o demo demo.cc
demof: demo.cc libprcoords.cc
$(CXX) $(CXXFLAGS) -DPRCOORDS_DEMO_FORCE_STANDALONE=1 -DPRCOORDS_NUM=float -DPRCOORDS_STON=stof -o demof demo.cc
demold: demo.cc libprcoords.cc
$(CXX) $(CXXFLAGS) -DPRCOORDS_DEMO_FORCE_STANDALONE=1 -DPRCOORDS_NUM='long double' -DPRCOORDS_STON=stold -o demold demo.cc
# Horray! We do not need import libraries.
# FIXME: COMMAND NOT BUILDING ON MY NIXOS
demoso: demo.cc $(LIB)prcoords.$(SO)
$(CXX) $(CXXFLAGS) -L. -l:$(LIB)prcoords.$(SO) -o demoso -DPRCOORDS_DLL demo.cc
nanobench.h:
wget -O nanobench.h https://github.com/martinus/nanobench/raw/master/src/include/nanobench.h
bench: libprcoords.o prcoords.h nanobench.h bench.cc
$(CXX) $(CXXFLAGS) -DPRCOORDS_BENCH $(DEFS) -o bench libprcoords.o bench.cc
.PHONY: clean help install uninstall
install: all
mkdir -p $(DESTDIR)$(PREFIX)/bin/prcoords-demo
install -s demoso -- $(DESTDIR)$(PREFIX)/bin/prcoords-demo
mkdir -p $(DESTDIR)$(PREFIX)/lib
install -m 644 -- libprcoords.a $(LIB)prcoords.$(SO) $(DESTDIR)$(PREFIX)/lib
uninstall:
rm -f -- $(DESTDIR)$(PREFIX)/bin/prcoords-demo $(DESTDIR)$(PREFIX)/lib/libprcoords.a $(DESTDIR)$(PREFIX)/lib/$(LIB)prcoords.$(SO)
clean:
$(RM) demo demof demold *.exe *.a *.o *.def *.dll *.obj *.lib *.exp *.obj bench
================================================
FILE: cpp/badmath.hh
================================================
/**
* Internal header for implementing "fast" sin(x*pi).
*/
#include <cmath>
namespace badmath {
// what are you gonna do about it? x can't be too big!
// this is supposed to turn into FMA where fast, and not invoke the fma() libc function otherwise.
// like how Julia's muladd() works, but at the mercy of the compiler.
template<typename T>
inline T red4(T x) {
return -4 * std::nearbyint(x * 0.25) + x;
}
// devmaster user "Nick"'s approximation formula
// https://web.archive.org/web/20171228230531/http://forum.devmaster.net/t/fast-and-accurate-sine-cosine/9648
template<typename T>
inline T sinpi_nick(T x) {
x = red4(x * 2); // = 0 to 2pi; nick-magic works on units of 0.5pi
T y = x * (2 - std::abs(x));
return y * (0.775 + 0.225 * std::abs(y));
}
template<typename T>
inline T sinpi_std(T x) {
return std::sin(x * M_PI);
}
template<typename T>
inline T sinpi(T x) {
#ifndef PRCOORDS_NO_BADMATH
return sinpi_nick(x);
#else
return sinpi_std(x);
#endif
}
template<typename T>
inline T cospi(T x) {
return sinpi(x + 0.5);
}
}
================================================
FILE: cpp/bench.cc
================================================
#include <iostream>
#include "badmath.hh"
#include "prcoords.h"
#define ANKERL_NANOBENCH_IMPLEMENT
#include "nanobench.h"
double uniform(ankerl::nanobench::Rng& rng, double a, double b){
return rng.uniform01() * (b - a) + a;
}
PRCoords rand_coord(ankerl::nanobench::Rng& rng){
return PRCoords{.lat = uniform(rng, -90, 90), .lon = uniform(rng, -180, 180)};
}
int main(){
using namespace badmath;
auto rng = ankerl::nanobench::Rng();
ankerl::nanobench::Bench().minEpochIterations(10000).run(
"nop", [&]() {
auto coord = rand_coord(rng);
ankerl::nanobench::doNotOptimizeAway(coord);
}
);
ankerl::nanobench::Bench().minEpochIterations(10000).run(
"wgs_gcj", [&]() {
auto coord = rand_coord(rng);
auto res = prcoords_wgs_gcj(coord);
ankerl::nanobench::doNotOptimizeAway(res);
}
);
ankerl::nanobench::Bench().minEpochIterations(10000).run(
"gcj_wgs", [&]() {
auto coord = rand_coord(rng);
auto res = prcoords_gcj_wgs(coord);
ankerl::nanobench::doNotOptimizeAway(res);
}
);
ankerl::nanobench::Bench().minEpochIterations(10000).run(
"gcj_wgs_bored", [&]() {
auto coord = rand_coord(rng);
auto res = prcoords_gcj_wgs_bored(coord);
ankerl::nanobench::doNotOptimizeAway(res);
}
);
ankerl::nanobench::Bench().minEpochIterations(10000).run(
"bd_wgs_bored", [&]() {
auto coord = rand_coord(rng);
auto res = prcoords_gcj_wgs_bored(coord);
ankerl::nanobench::doNotOptimizeAway(res);
}
);
ankerl::nanobench::Bench().minEpochIterations(10000).run(
"gcj_bd", [&]() {
auto coord = rand_coord(rng);
auto res = prcoords_gcj_bd(coord);
ankerl::nanobench::doNotOptimizeAway(res);
}
);
return 0;
}
================================================
FILE: cpp/bench4.sh
================================================
#!/bin/sh
bench_to_file() {
make clean
make bench XCXXFLAGS="$1"
./bench > bench_out/$2.md
}
native='-march=native'
stdsin='-DPRCOORDS_NO_BADMATH'
if (( ! KEEP_GOVNOR )); then
OL_GOVNOR=$(cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor)
echo performance | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
fi
bench_to_file "$native" 'native_nick'
bench_to_file "$native $stdsin" 'native_stdsin'
bench_to_file "" 'nick'
bench_to_file "$stdsin" 'stdsin'
if [[ -n $OL_GOVNOR ]]; then
echo $OL_GOVNOR | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
fi
================================================
FILE: cpp/bench_out/README.md
================================================
# bench_out
All four files are made by nanobench; just do `./bench4.sh`.
* `nick` is the version with Nick's fast sinpi.
* `std` is the version with sinpi implemented by `std::sin(M_PI * x)`.
* The ones with `native_` in front are built with `-march=native`.
All the other flags are per Makefile: unsafe math optimizations, no math errno,
you know the drill.
The native versions are just 10% faster. The real win comes from using Nick's
approximation, which quarters the runtime.
There seems to be no real damage to the output. I mean, nick is at most 1e-3
off. That's appropriate when we are working in how many meters to shift a
point.
* Compiler: GCC 13.2.0
* CPU: Ryzen 5 3600
* OS: NixOS 24.05pre, Linux 6.6.28
## Update: more agressive nicking
I also applied Nick's approximation to the `arclen` calculation in GCJ. As
expected of a more important divisor, some visible damage to the output is
seen, but the magnitude remians in the 1e-6 range. I consider that acceptable
given the performance gain (see the files!); it's now the default.
\[That does make the `bored` conversion a bit pointless. Hmm, idk.\]
`bd` calculation also now uses nick. It also gets benched.
Going native seems to cause a 15% regression on `bd`, std or nick.
Might be a good idea to look into that, or at least see what clang does.
Anyone wishing to turn off nick can use the `-DPRCOORDS_NO_BADMATH` define.
There *might* be a point in turning off nick for specific parts of the
calculation, but I don't want to spend time on that.
================================================
FILE: cpp/bench_out/native_nick.md
================================================
Warning, results might be unstable:
* CPU frequency scaling enabled: CPU 0 between 550.0 and 4,208.0 MHz
Recommendations
* Use 'pyperf system tune' before benchmarking. See https://github.com/psf/pyperf
| ns/op | op/s | err% | ins/op | cyc/op | IPC | bra/op | miss% | total | benchmark
|--------------------:|--------------------:|--------:|----------------:|----------------:|-------:|---------------:|--------:|----------:|:----------
| 4.12 | 242,648,826.64 | 0.4% | 22.00 | 16.60 | 1.325 | 0.00 | 0.0% | 0.01 | `nop`
| 30.80 | 32,472,208.69 | 3.6% | 223.00 | 121.17 | 1.840 | 2.00 | 0.0% | 0.01 | `wgs_gcj`
| 37.95 | 26,349,634.73 | 0.2% | 238.00 | 149.56 | 1.591 | 4.00 | 0.0% | 0.01 | `gcj_wgs`
| 157.44 | 6,351,722.84 | 2.1% | 683.36 | 622.28 | 1.098 | 13.03 | 2.3% | 0.02 | `gcj_wgs_bored`
| 154.01 | 6,493,059.75 | 1.3% | 683.44 | 613.84 | 1.113 | 13.03 | 2.3% | 0.02 | `bd_wgs_bored`
| 70.30 | 14,224,263.54 | 3.0% | 360.39 | 274.90 | 1.311 | 49.20 | 3.0% | 0.01 | `gcj_bd`
================================================
FILE: cpp/bench_out/native_stdsin.md
================================================
Warning, results might be unstable:
* CPU frequency scaling enabled: CPU 0 between 550.0 and 4,208.0 MHz
Recommendations
* Use 'pyperf system tune' before benchmarking. See https://github.com/psf/pyperf
| ns/op | op/s | err% | ins/op | cyc/op | IPC | bra/op | miss% | total | benchmark
|--------------------:|--------------------:|--------:|----------------:|----------------:|-------:|---------------:|--------:|----------:|:----------
| 4.09 | 244,330,932.16 | 0.5% | 22.00 | 16.60 | 1.325 | 0.00 | 0.0% | 0.01 | `nop`
| 196.22 | 5,096,191.73 | 0.3% | 1,279.11 | 780.29 | 1.639 | 160.01 | 7.2% | 0.02 | `wgs_gcj`
| 197.34 | 5,067,445.81 | 0.3% | 1,294.41 | 782.36 | 1.655 | 162.02 | 7.0% | 0.02 | `gcj_wgs`
| 623.01 | 1,605,113.03 | 0.6% | 3,861.91 | 2,462.12 | 1.569 | 489.22 | 5.6% | 0.07 | `gcj_wgs_bored`
| 622.11 | 1,607,439.62 | 0.4% | 3,856.47 | 2,461.61 | 1.567 | 488.46 | 5.6% | 0.08 | `bd_wgs_bored`
| 89.76 | 11,141,416.00 | 0.3% | 540.45 | 356.74 | 1.515 | 77.21 | 5.5% | 0.01 | `gcj_bd`
================================================
FILE: cpp/bench_out/nick.md
================================================
Warning, results might be unstable:
* CPU frequency scaling enabled: CPU 0 between 550.0 and 4,208.0 MHz
Recommendations
* Use 'pyperf system tune' before benchmarking. See https://github.com/psf/pyperf
| ns/op | op/s | err% | ins/op | cyc/op | IPC | bra/op | miss% | total | benchmark
|--------------------:|--------------------:|--------:|----------------:|----------------:|-------:|---------------:|--------:|----------:|:----------
| 3.25 | 307,628,660.33 | 0.4% | 22.00 | 12.97 | 1.696 | 0.00 | 0.0% | 0.01 | `nop`
| 45.60 | 21,931,100.65 | 0.8% | 448.00 | 179.13 | 2.501 | 38.00 | 0.0% | 0.01 | `wgs_gcj`
| 59.09 | 16,922,136.13 | 2.1% | 465.00 | 231.72 | 2.007 | 40.00 | 0.0% | 0.01 | `gcj_wgs`
| 198.70 | 5,032,812.17 | 0.6% | 1,365.35 | 779.44 | 1.752 | 121.13 | 0.3% | 0.02 | `gcj_wgs_bored`
| 197.66 | 5,059,121.12 | 0.5% | 1,364.69 | 774.35 | 1.762 | 121.07 | 0.2% | 0.02 | `bd_wgs_bored`
| 58.40 | 17,123,351.22 | 0.4% | 391.40 | 227.11 | 1.723 | 55.21 | 2.7% | 0.01 | `gcj_bd`
================================================
FILE: cpp/bench_out/stdsin.md
================================================
Warning, results might be unstable:
* CPU frequency scaling enabled: CPU 0 between 550.0 and 4,208.0 MHz
Recommendations
* Use 'pyperf system tune' before benchmarking. See https://github.com/psf/pyperf
| ns/op | op/s | err% | ins/op | cyc/op | IPC | bra/op | miss% | total | benchmark
|--------------------:|--------------------:|--------:|----------------:|----------------:|-------:|---------------:|--------:|----------:|:----------
| 3.24 | 308,253,800.28 | 0.2% | 22.00 | 12.97 | 1.696 | 0.00 | 0.0% | 0.01 | `nop`
| 216.41 | 4,620,855.79 | 6.9% | 1,315.38 | 853.91 | 1.540 | 160.04 | 7.2% | 0.03 | :wavy_dash: `wgs_gcj` (Unstable with ~10,854.4 iters. Increase `minEpochIterations` to e.g. 108544)
| 206.03 | 4,853,603.19 | 1.4% | 1,332.00 | 811.94 | 1.641 | 162.03 | 7.0% | 0.03 | `gcj_wgs`
| 653.44 | 1,530,359.50 | 1.0% | 3,973.24 | 2,546.70 | 1.560 | 488.60 | 5.6% | 0.08 | `gcj_wgs_bored`
| 653.92 | 1,529,245.44 | 0.6% | 3,976.15 | 2,533.60 | 1.569 | 488.87 | 5.6% | 0.08 | `bd_wgs_bored`
| 93.34 | 10,713,089.73 | 0.4% | 543.42 | 361.83 | 1.502 | 77.21 | 5.5% | 0.01 | `gcj_bd`
================================================
FILE: cpp/demo.cc
================================================
/**
* People's Rectified Coordinates, C++ demo.
*/
#if PRCOORDS_DEMO_FORCE_STANDALONE
#include "libprcoords.cc"
#else
#include "prcoords.h"
#endif
#include <iostream>
#include <sstream>
#include <iomanip>
#include <string>
using namespace std;
#ifndef PRCOORDS_STON
#define PRCOORDS_STON stod
#endif
std::string show_coord(PRCoords v) {
std::stringstream stream;
stream << std::fixed << std::setprecision(8) << v.lat << ", " << v.lon;
return stream.str();
}
PRCoords parse_coord(const string& s) {
int cut = s.find(", ");
return PRCoords{
PRCOORDS_STON(s.substr(0, cut)),
PRCOORDS_STON(s.substr(cut + 1))
};
}
int main(void) {
string input;
while (getline(cin, input))
{
PRCoords v = std::move(parse_coord(input));
cout
<< "w2g\t" << show_coord(prcoords_wgs_gcj(v)) << endl
<< "w2b\t" << show_coord(prcoords_wgs_bd(v)) << endl
<< "g2b\t" << show_coord(prcoords_gcj_bd(v)) << endl
<< "g2wQ\t" << show_coord(prcoords_gcj_wgs(v)) << endl
<< "b2wQ\t" << show_coord(prcoords_bd_wgs(v)) << endl
<< "b2gQ\t" << show_coord(prcoords_bd_gcj(v)) << endl
<< "g2wP\t" << show_coord(prcoords_gcj_wgs_bored(v)) << endl
<< "b2wP\t" << show_coord(prcoords_bd_wgs_bored(v)) << endl
<< "b2gP\t" << show_coord(prcoords_bd_gcj_bored(v)) << endl
<< endl;
}
}
================================================
FILE: cpp/libprcoords.cc
================================================
/**
* People's Rectified Coordinates, C++11 implementation
* Should yield a C-compatible ABI.
*/
#include "prcoords.h"
#include <cmath>
#include <functional>
#include <cassert>
#include "badmath.hh"
#ifndef M_PI
#define M_PI ((PRCOORDS_NUM) (3.14159265358979323846L))
#endif
// Assume
#ifndef __has_builtin
# define __has_builtin(x) 0
#endif
#ifndef NDEBUG
#define assume(R) assert(R)
#elif __has_builtin(__builtin_assume)
#define assume(R) __builtin_assume(R)
#elif __has_builtin(__builtin_unreachable)
#define assume(R) ((R) ? (void) 0 : __builtin_unreachable ())
#elif 1200 <= _MSC_VER
#define assume(R) __assume(R)
#else
#define assume(R) ((void) 0)
#endif
#define assume_angle(x, a) assume(x >= -a && x <= a)
#define assume_coord(c) do { \
assume_angle(c.lat, 90); \
assume_angle(c.lon, 180);\
} while(0)
// enforces PRCOORDS_NUM
using std::sin;
using std::cos;
using std::sqrt;
using std::atan2;
using std::pow;
using std::fabs;
using badmath::sinpi;
using badmath::cospi;
/// Krasovsky 1940 ellipsoid
/// @const
const static PRCOORDS_NUM GCJ_A = 6378245;
const static PRCOORDS_NUM GCJ_EE = 0.00669342162296594323; // f = 1/298.3; e^2 = 2*f - f**2
const static PRCOORDS_NUM BD_DLAT = 0.0060;
const static PRCOORDS_NUM BD_DLON = 0.0065;
/// Epsilon to use for "exact" iterations.
/// Wanna troll? Use Number.EPSILON. 1e-13 in 15 calls for gcj.
/// @const
const static PRCOORDS_NUM PRCOORDS_EPS = 1e-5;
typedef PRCoords (*PRCOp)(PRCoords);
/// These conversions are for bored people: too accurate to be useful
/// given pseudo-random noises added to GCJ.
///
/// Should we implement a 2-iter version?
/// Just "wgs = wgs - (fwd(wgs) - bad);", repeated twice.
template<PRCOp fwd, PRCOp rev>
PRCOORDS_LOCAL static PRCoords bored_reverse_conversion(PRCoords bad) {
assume_coord(bad);
PRCoords wgs = rev(bad);
PRCoords diff{INFINITY, INFINITY};
int i = 0;
while ((fabs(diff.lat) + fabs(diff.lon)) > PRCOORDS_EPS && i++ < 10) {
diff = fwd(wgs) - bad;
wgs = wgs - diff;
}
return wgs;
}
extern "C" {
PRCoords prcoords_wgs_gcj(PRCoords wgs) {
assume_coord(wgs);
PRCOORDS_NUM x = wgs.lon - 105, y = wgs.lat - 35;
// These distortion functions accept (x = lon - 105, y = lat - 35).
// They return distortions in terms of arc lengths, in meters.
//
// In other words, you can pretty much figure out how much you will be off
// from WGS-84 just through evaulating them...
//
// For example, at the (mapped) center of China (105E, 35N), you get a
// default deviation of <300, -100> meters.
#ifndef APPROX
PRCOORDS_NUM dLat_m = -100 + 2 * x + 3 * y + 0.2 * y * y + 0.1 * x * y
+ 0.2 * sqrt(fabs(x)) + (
2 * sinpi(x * 6) + 2 * sinpi(x * 2)
+ 2 * sinpi(y) + 4 * sinpi(y / 3)
+ 16 * sinpi(y / 12) + 32 * sinpi(y / 30)
) * 20 / 3;
PRCOORDS_NUM dLon_m = 300 + x + 2 * y + 0.1 * x * x + 0.1 * x * y
+ 0.1 * sqrt(fabs(x)) + (
2 * sinpi(x * 6) + 2 * sinpi(x * 2)
+ 2 * sinpi(x) + 4 * sinpi(x / 3)
+ 15 * sinpi(x / 12) + 30 * sinpi(x / 30)
) * 20 / 3;
#else
// Approximation code from julia side. I should probably
// extract the xy-to-ne thing, but that would mean making the whole
// program templates. Not today.
// FIXME: The coefficients are giving me ridiculously large numbers!
PRCOORDS_NUM dLat_m = 0;
PRCOORDS_NUM dLon_m = 0;
#endif
// NOTE: Using sinpi_nick causes the results to be off by 1e-6.
// That's acceptable casualty.
// Don't like it? Use PRCOORDS_NO_BADMATH.
PRCOORDS_NUM radLat = wgs.lat / 180;
PRCOORDS_NUM magic = 1 - GCJ_EE * pow(sinpi(radLat), 2); // just a common expr
// [[:en:Latitude#Length_of_a_degree_of_latitude]]
PRCOORDS_NUM lat_deg_arclen = (M_PI / 180) * (GCJ_A * (1 - GCJ_EE)) / pow(magic, 1.5);
// [[:en:Longitude#Length_of_a_degree_of_longitude]]
PRCOORDS_NUM lon_deg_arclen = (M_PI / 180) * (GCJ_A * cospi(radLat) / sqrt(magic));
// The screwers pack their deviations into degrees and disappear.
// Note how they are mixing WGS-84 and Krasovsky 1940 ellipsoids here...
return PRCoords{
wgs.lat + (dLat_m / lat_deg_arclen),
wgs.lon + (dLon_m / lon_deg_arclen),
};
}
PRCoords prcoords_gcj_wgs(PRCoords gcj) {
assume_coord(gcj);
return gcj - (prcoords_wgs_gcj(gcj) - gcj);
}
PRCoords prcoords_gcj_bd(PRCoords gcj) {
assume_coord(gcj);
PRCOORDS_NUM x = gcj.lon;
PRCOORDS_NUM y = gcj.lat;
// trivia: pycoordtrans actually describes how these values are calculated
PRCOORDS_NUM r = sqrt(x * x + y * y) + 0.00002 * sinpi(y * 3000 / 180);
PRCOORDS_NUM t = atan2(y, x) + 0.000003 * cospi(x * 3000 / 180);
// Hard-coded default deviations again!
return PRCoords{
r * sin(t) + BD_DLAT,
r * cos(t) + BD_DLON,
};
}
PRCoords prcoords_bd_gcj(PRCoords bd) {
assume_coord(bd);
PRCOORDS_NUM x = bd.lon - BD_DLON;
PRCOORDS_NUM y = bd.lat - BD_DLAT;
PRCOORDS_NUM r = sqrt(x * x + y * y) - 0.00002 * sinpi(y * 3000 / 180);
PRCOORDS_NUM t = atan2(y, x) - 0.000003 * cospi(x * 3000 / 180);
return PRCoords{
r * sin(t),
r * cos(t),
};
}
PRCoords prcoords_wgs_bd(PRCoords wgs) {
return prcoords_gcj_bd(prcoords_wgs_gcj(wgs));
}
PRCoords prcoords_bd_wgs(PRCoords bd) {
return prcoords_gcj_wgs(prcoords_bd_gcj(bd));
}
PRCoords prcoords_gcj_wgs_bored(PRCoords gcj) {
return bored_reverse_conversion<prcoords_wgs_gcj, prcoords_gcj_wgs>(gcj);
}
PRCoords prcoords_bd_gcj_bored(PRCoords bd) {
return bored_reverse_conversion<prcoords_gcj_bd, prcoords_bd_gcj>(bd);
}
PRCoords prcoords_bd_wgs_bored(PRCoords bd) {
return bored_reverse_conversion<prcoords_wgs_bd, prcoords_bd_wgs>(bd);
}
}
#if PRCOORDS_TEST
#include <iostream>
#include <type_traits>
std::string show_coord(PRCoords v) {
return std::to_string(v.lat) + ", " + std::to_string(v.lon);
}
int main(void) {
std::cout << std::is_pod<PRCoords>::value << std::endl
<< show_coord(prcoords_wgs_gcj(PRCoords{35, 105})) << std::endl
<< show_coord(prcoords_wgs_bd(PRCoords{35, 105})) << std::endl
<< show_coord(prcoords_wgs_gcj(PRCoords{34, 106})) << std::endl
<< show_coord(prcoords_wgs_bd(PRCoords{34, 106})) << std::endl;
}
#endif
================================================
FILE: cpp/prcoords.h
================================================
/**
* People's Rectified Coordinates, C/C++ Header.
*/
#ifndef PRCOORDS_H
#define PRCOORDS_H
/** May be changed to "long double" for bored folks
* (need an "L" suffix on literals for the seriously bored)
* "float" is not recommended
*/
#ifndef PRCOORDS_NUM
#define PRCOORDS_NUM double
#endif
// Generic helper definitions for shared library support
#if defined _WIN32 || defined __CYGWIN__
#define PRCOORDS_HELPER_DLL_IMPORT __declspec(dllimport)
#define PRCOORDS_HELPER_DLL_EXPORT __declspec(dllexport)
#define PRCOORDS_HELPER_DLL_LOCAL
#else
#if __GNUC__ >= 4 // works on clang lmao
#define PRCOORDS_HELPER_DLL_IMPORT __attribute__ ((visibility ("default")))
#define PRCOORDS_HELPER_DLL_EXPORT __attribute__ ((visibility ("default")))
#define PRCOORDS_HELPER_DLL_LOCAL __attribute__ ((visibility ("hidden")))
#else
#define PRCOORDS_HELPER_DLL_IMPORT
#define PRCOORDS_HELPER_DLL_EXPORT
#define PRCOORDS_HELPER_DLL_LOCAL
#endif
#endif
#ifdef PRCOORDS_DLL // defined if PRCOORDS is compiled as a DLL
#ifdef PRCOORDS_DLL_EXPORTS // defined if we are building the PRCOORDS DLL (instead of using it)
#define PRCOORDS_API PRCOORDS_HELPER_DLL_EXPORT
#else
#define PRCOORDS_API PRCOORDS_HELPER_DLL_IMPORT
#endif // PRCOORDS_DLL_EXPORTS
#define PRCOORDS_LOCAL PRCOORDS_HELPER_DLL_LOCAL
#else // PRCOORDS_DLL is not defined: this means PRCOORDS is a static lib.
#define PRCOORDS_API
#define PRCOORDS_LOCAL
#endif // PRCOORDS_DLL
#ifdef __cplusplus
#define PRCOORDS_CONSTEXPR constexpr
#if __cplusplus >= 201300L
#define PRCOORDS_CONSTEXPR14 constexpr
#else
#define PRCOORDS_CONSTEXPR14 inline
#endif // c++14, including 1y
extern "C" {
#else
#include <stdbool.h>
#define PRCOORDS_CONSTEXPR inline
#endif
typedef struct PRCoords {
PRCOORDS_NUM lat, lon;
} PRCoords;
// make them pure
/// GCJ APIs should all probably turn on china-checks.
/// But we should allow some override.... Damn C.
PRCOORDS_API PRCoords prcoords_wgs_gcj(PRCoords);
PRCOORDS_API PRCoords prcoords_gcj_wgs(PRCoords);
PRCOORDS_API PRCoords prcoords_gcj_bd(PRCoords);
PRCOORDS_API PRCoords prcoords_bd_gcj(PRCoords);
PRCOORDS_API PRCoords prcoords_wgs_bd(PRCoords);
PRCOORDS_API PRCoords prcoords_bd_wgs(PRCoords);
PRCOORDS_API PRCoords prcoords_gcj_wgs_bored(PRCoords);
PRCOORDS_API PRCoords prcoords_bd_gcj_bored(PRCoords);
PRCOORDS_API PRCoords prcoords_bd_wgs_bored(PRCoords);
PRCOORDS_LOCAL static PRCOORDS_CONSTEXPR bool prcoords_in_china(const PRCoords& a) {
// cut out some
return a.lat >= 16.7414 && a.lon >= 72.004 && a.lat <= 55.8271 && a.lon <= 137.8347;
}
#ifdef __cplusplus
}
PRCOORDS_LOCAL inline PRCoords operator- (const PRCoords& a, const PRCoords& b) {
return PRCoords {
a.lat - b.lat,
a.lon - b.lon
};
}
// for sorting
// lat
// |
// -<-o---lon (quadrants III, IV and x < 0)
// < | <
PRCOORDS_LOCAL inline bool operator< (const PRCoords& a, const PRCoords& b) {
return a.lat < b.lat || (a.lat == b.lat && a.lon < b.lon);
}
PRCOORDS_LOCAL inline bool operator> (const PRCoords& a, const PRCoords& b) { return b < a; }
PRCOORDS_LOCAL inline bool operator<=(const PRCoords& a, const PRCoords& b) { return !(a > b); }
PRCOORDS_LOCAL inline bool operator>=(const PRCoords& a, const PRCoords& b) { return !(a < b); }
PRCOORDS_LOCAL inline bool operator==(const PRCoords& a, const PRCoords& b) {
return a.lat == b.lat && a.lon == b.lon;
}
PRCOORDS_LOCAL inline bool operator!=(const PRCoords& a, const PRCoords& b) { return !(a == b); }
#endif // __cplusplus
#endif // header
================================================
FILE: docs/demo.html
================================================
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<!--
Snapshot from http://jsbin.com/zonafut/37/edit
-->
<meta name="viewport" content="width=device-width">
<meta name="author" content="Mingye Wang">
<meta name="description" content="A Public Domain GCJ-02/BD-09 to WGS-84 Deobfscator (not eviltransform, but PRCoords)">
<link href="https://Artoria2e5.github.io/PRCoords/Globe%2C_distorted_China.svg" type="image/svg+xml" rel="icon">
<link rel="schema.DCTERMS" href="http://purl.org/dc/terms/">
<title>People Rectify Coordinates</title>
<style id="jsbin-css">
body {
font-family: sans-serif;
margin: 0 auto;
max-width: 50em;
padding: 0 1em;
}
@media print {
body {
max-width: none;
padding: 0;
}
}
h1, h2, h3, h4, h5, h6 {
font-family: serif;
}
dt {
font-weight: bold;
}
h1, h2, h3 {
border-bottom: 1px solid #a2a9b1;
}
input[type='number'].dnum {
-moz-appearance:textfield;
}
input[type='number'].dnum::-webkit-outer-spin-button,
input[type='number'].dnum::-webkit-inner-spin-button {
-webkit-appearance: none;
}
input[type='number'] {
width: 4em;
}
input[type='number'][name^=s] {
width: 6em
}
#deg-in input[type='number'] {
width: 8em
}
#output > table {
width: 100%
}
img.logo {
position: absolute;
top: 1em;
right: 1em;
border: none;
}
footer {
font-size: smaller;
}
table {
border-collapse: collapse;
}
td {
border: thin solid #a2a9b1;
padding: 0.2em 0.4em;
}
tbody td:nth-child(n+2) {
font-family: monospace;
}
#egcj td:nth-child(1), #ebd td:nth-child(1), #bbd td:nth-child(1) {
background: LightSalmon;
}
#dgcj td:nth-child(1), #dbd td:nth-child(1), #bgcj td:nth-child(1) {
background: PaleGreen;
}
#cgcj td:nth-child(1), #cbd td:nth-child(1), #bcgcj td:nth-child(1) {
background: Aquamarine;
}
</style>
</head>
<body onload="from_query()">
<h1>People Rectify Coordinates</h1>
<div style="margin-top: -1em"><small>With <a href="https://en.wikipedia.org/wiki/GCJ-02">restrictions</a> from the People’s Republic of China</small></div>
<a href="https://commons.wikimedia.org/wiki/File:Globe,_distorted_China.svg">
<img class="logo" src="https://Artoria2e5.github.io/PRCoords/Globe%2C_distorted_China.svg" width="100" height="100" alt="logo: China? Where?"></a>
<article>
<section>
<h2>Input</h2>
<form id="inputc" onsubmit="return false"><!-- also make edge happy -->
<ul>
<li><label>Degrees:</label><ul id="deg-in">
<li><label>lat=</label> <input type="number" class="dnum" name="lat" value="35" step="any" min="-90" max="90">;
<li><label>lon=</label> <input type="number" class="dnum" name="lon" value="105" step="any" min="-180" max="180">.</ul>
<li><label>Or dms:</label><ul id="dms-in">
<li><label>lat=</label>
<input type="number" name="dlat" min="0" max="90" step="1" value="35">°
<input type="number" name="mlat" min="0" max="59" step="1" value="0">′
<input type="number" name="slat" min="0" max="60" value="0" step=any>″
<select name="hlat"><option>N</option><option>S</option></select>;
<li><label>lon=</label>
<input type="number" name="dlon" min="0" max="180" step="1" value="105">°
<input type="number" name="mlon" min="0" max="59" step="1" value="0">′
<input type="number" name="slon" min="0" max="69" value="0" step=any>″
<select name="hlon"><option>E</option><option>W</option></select>.</ul></ul>
<button onclick="return fill_output() && false">Screw that!</button>
</form>
<script src="https://cdn.jsdelivr.net/npm/prcoords@1/js/PRCoords.min.js" onerror="this.src='../js/PRCoords.js'"></script>
<h2>Results</h2>
<table id="output">
<tr>
<th>Operation
<th>Result
<th title="How wrong have I been?">ΔObfs/m
<th title="How precise is this operation?">ΔRoundtrip/m</tr>
<tr id="egcj"><td>WGS → GCJ<td><td><td>
<tr id="ebd"><td>WGS → BD<td><td><td>
<tr id="dgcj"><td>GCJ → WGS<td><td><td>
<tr id="dbd"><td>BD → WGS<td><td><td>
<tr id="cgcj"><td>GCJ →<sup>cai</sup> WGS<td><td><td>
<tr id="cbd"><td>BD →<sup>cai</sup> WGS<td><td><td>
<tr id="bbd"><td>GCJ → BD<td><td><td>
<tr id="bgcj"><td>BD → GCJ<td><td><td>
<tr id="bcgcj"><td>BD →<sup>cai</sup> GCJ<td><td><td>
</table>
<p><a id="permalink" href="https://artoria2e5.github.io/PRCoords/demo">Permalink to this result</a>.
Toggle sections: <a href="javascript:toggle('notes')">Notes</a>, <a href="javascript:toggle('faq')">FAQ</a>, <a href="javascript:toggle('footer')">footer</a>.
And <a href="javascript:window.print()">print</a>.
</section>
<section id="notes">
<h2>Notes</h2>
<ol>
<li>Caijun’s iterative method is included for precise decoding.
It's most useful for bored folks whose GPS data is pretty accurate
and GCJ-02 obfuscation not tainted by the original
<abbr title="linear congruential pseudo-random number generator">LCPRNG</abbr>.
<p>If you are doing Wikipedia or any kind of archival work, use it to avoid introducing extra error.
<li>BD is defined in terms of GCJ, hence the last three functions.
<li>This demo omits the “in China” sanity check. Data regarding
Baidu’s behavior with overseas maps is needed for further
decisions. Observations:<ul>
<li>Unlike Google Maps, Baidu's map in Hong Kong is fully subject to
BD-09 ∘ GCJ-02 chained distortions.
<li>Coordinates in Russia, outside of the sanity check rectangle, uses WGS-84 or and/or friends.
<li>TODO: check along the boundary.
</ul>
</ol>
</section>
<section id="faq">
<h2>FAQ</h2>
<dl>
<dt id="what">What is this all about?</dt>
<dd>The PRC government requires all local map services to use an
obfuscated, <a href="https://github.com/Artoria2e5/PRCoords/blob/1ea97f2/js/PRCoords.js#L102-L109">
deviation-orienated</a> coordinate system.
Click on the “restriction” link to read the full Wikipedia article.</dd>
<dt id="why">Why should I care?</dt>
<dd>With half a kilometer of deviation, GCJ-02 and friends fucks up your
<a href="https://github.com/iitc-project/ingress-intel-total-conversion/blob/75a517b/plugins/fix-googlemap-china-offset.user.js">Ingress games</a>,
causes <a href="https://www.zhihu.com/question/29806566/answer/46099380">crazy errors</a>
in elevation profiles along cycle routes, and cheerfully leads you
into roadside ditches plus a bone fracture.</dd>
<dt id="google">Why doesn’t Google/Bing correct its Chinese data served to global users?</dt>
<dd><a href="https://productforums.google.com/forum/#!topic/maps/NunCUpRwLA0">I don’t know</a>.
Perhaps they are afraid of getting fined or further kicked out of China.
Maybe try <a href="https://openstreetmap.org">OpenStreetMap</a> next time?</dd>
<dt id="wheel">Why are you writing another implementation?</dt>
<dd><a href="https://github.com/Artoria2e5/PRCoords#why-another-wheel">Because I got bored</a>.</dd>
<dt id="caijun">How does Caijun’s iterative method work?</dt>
<dd>Cai has explained the method in full in his
<a href="https://github.com/caijun/geoChina/blob/5c6284b/R/cst.R#L101-L107"> R implementation</a>. Go read it, or read Wikipedia.
</dl>
</section>
</article>
<footer id="footer">
<hr>
Powered by <a href="https://github.com/Artoria2e5/PRCoords">PRCoords</a>. Try playing with <code>window.PRCoords</code> in your console!
<p>
<a rel="license"
href="http://creativecommons.org/publicdomain/zero/1.0/">
<img src="https://licensebuttons.net/p/zero/1.0/88x31.png" style="border-style: none;" alt="CC0"></a>
<br>
To the extent possible under law,
<a rel="DCTERMS.publisher"
href="https://zh.wikipedia.org/wiki/User:Artoria2e5">
<span property="DCTERMS.title">Mingye Wang</span></a>
has waived all copyright and related or neighboring rights to
<span property="DCTERMS.title">People Rectify Coordinates</span>.
This work is published from:
<span property="geo.country"
content="US" about="https://artoria2e5.github.io/PRCoords/demo">
United States</span>.</p>
</footer>
<script>
"use strict";
// dms/deg
var coordInfo = {
'N': [+1, 'lat'],
'S': [-1, 'lat'],
'E': [+1, 'lon'],
'W': [-1, 'lon'],
}
var coordBack = {
'+lat': 'N',
'-lat': 'S',
'+lon': 'E',
'-lon': 'W',
}
function dmsToDec(d, m, s, hemisphere = 'N', type = '') {
if (type !== '') {
if (coordInfo[hemisphere][1] !== type) {
throw new RangeError('' + hemisphere + ' ' + type)
}
}
return coordInfo[hemisphere][0] * Math.round(((+d) + (+m)/60 + (+s)/3600)*1e8)/1e8
}
function decToDms(dec, type) {
var sign = (+dec) >= 0 ? 1 : -1
var hemi = coordBack[(sign == -1 ? '-' : '+') + type]
dec *= sign
var d = Math.floor(dec)
var m = Math.floor((dec-d)*60)
var s = Math.round((dec-d-m/60)*3600*1e4)/1e4
return [d, m, s, hemi]
}
// TODO refactor
// link back to the referrer if we can recognize it
var relink = function(lat, lon, ref) {
try {
var uref = new URL(ref)
} catch (e) {
return
}
if (uref.hostname == "tools.wmflabs.org" &&
uref.pathname.startsWith("/geohack")) {
var uparams = new URLSearchParams(uref.search.slice(1))
var uparam = uparams.get("params").split('_')
uparam[0] = Math.abs(lat)
uparam[1] = coordBack[(+lat < 0 ? '-' : '+') + 'lat']
uparam[2] = Math.abs(lon)
uparam[3] = coordBack[(+lon < 0 ? '-' : '+') + 'lon']
uparams.set("params", uparam.join('_'))
uref.search = uparams.toString()
return uref
}
}
// hooks
var inputs = document.getElementById('inputc')
function updFromDeg (ev) {
if (ev.target.value === '')
return;
var type = ev.target.name
var dmsh = [
inputs['d'+type],
inputs['m'+type],
inputs['s'+type],
inputs['h'+type],
]
;[
dmsh[0].value,
dmsh[1].value,
dmsh[2].value,
dmsh[3].value,
] = decToDms(+ev.target.value, type)
}
function updFromDms (ev) {
if (ev.target.value === '')
return;
var type = ev.target.name.substring(1)
inputs[type].value = dmsToDec(
inputs['d'+type].value,
inputs['m'+type].value,
inputs['s'+type].value,
inputs['h'+type].value,
type
)
}; // <- happy edge
// note: make edge happy:
// * make an array for a iterator in Edge
// * Don't use spread or Edge freaks out
for (let i of Array.from(inputs.querySelectorAll('#deg-in input')))
i.onchange = updFromDeg
for (let i of Array.from(inputs.querySelectorAll('#dms-in input, #dms-in select')))
i.onchange = updFromDms
// handler..
var a_perm = document.getElementById('permalink')
var baseurl = a_perm.href
function fill_output() {
// Edge shit
a_perm = a_perm || document.getElementById('permalink')
baseurl = baseurl || a_perm.href
// end Edge
var get_inverse = function (fname) {
var comp = fname.split('_')
return comp[1] + '_' + comp[0]/* +
(bored &&
comp[0] !== 'wgs' &&
!(comp[0] === 'gcj' && comp[1] === 'bd')) ?
'_bored' : ''*/
}
var fnames = {
dgcj: 'gcj_wgs',
dbd: 'bd_wgs',
egcj: 'wgs_gcj',
ebd: 'wgs_bd',
cgcj: 'gcj_wgs_bored',
cbd: 'bd_wgs_bored',
bgcj: 'bd_gcj',
bbd: 'gcj_bd',
bcgcj: 'bd_gcj_bored',
}
var incoords = {
lat: +inputs.lat.value,
lon: +inputs.lon.value,
}
console.log(incoords)
var coordToHtml = function(c) {
var lat = c.lat.toFixed(8)
var lon = c.lon.toFixed(8)
var ret = '(' + lat + ', ' + lon + ')'
var relinked = relink(lat, lon, document.referrer)
if (relinked) {
var a_boi = document.createElement("a")
a_boi.innerText = ret
a_boi.href = relinked
ret = a_boi.outerHTML
}
ret += '<br/>'
var dms = decToDms(lat, 'lat')
ret += dms[0] + '°' + dms[1] + '′' + dms[2] + '″ ' + dms[3] + ', '
dms = decToDms(lon, 'lon')
return ret + dms[0] + '°' + dms[1] + '′' + dms[2] + '″ ' + dms[3]
}
for (var i in fnames) {
var row = document.getElementById(i)
var fun = PRCoords[fnames[i]]
var inv = PRCoords[get_inverse(fnames[i])]
var out = Array.from(row.childNodes).slice(1)
var res = fun(incoords, false)
var dObfs = PRCoords.distance(res, incoords)
var dRoundtrip = PRCoords.distance(inv(res, false), incoords)
out[0].innerHTML = coordToHtml(res)
out[1].innerText = dObfs.toExponential()
out[2].innerText = dRoundtrip.toExponential()
}
a_perm.href = baseurl + '?lat=' + incoords.lat + '&lon=' + incoords.lon // + '#output'
return false
}
/// *** polyfill handling *** ///
// https://philipwalton.com/articles/loading-polyfills-only-when-needed/
function loadScript(src, done) {
var js = document.createElement('script')
js.src = src
js.onload = function() {
done()
}
js.onerror = function() {
done(new Error('Failed to load script ' + src))
}
document.head.appendChild(js)
}
/// ^^^ polyfill handling ^^^ ///
function __from_query() {
function qe(s, d) {
return s ? s : d
}
try {
let params = new URLSearchParams(location.search.slice(1))
inputs.lat.value = qe(params.get('lat'), inputs.lat.value)
inputs.lon.value = qe(params.get('lon'), inputs.lon.value)
// trigger a dms update
var event = new Event("change")
for (let i of Array.from(inputs.querySelectorAll('#deg-in input')))
i.dispatchEvent(event)
}
catch (e) {
console.error(e)
}
return fill_output()
}
function from_query() {
if (typeof URLSearchParams !== 'undefined') {
return __from_query()
} else {
// https://github.com/WebReflection/url-search-params
loadScript("https://cdn.rawgit.com/WebReflection/url-search-params/774ee42/build/url-search-params.js", __from_query)
}
}
function toggle(id) {
var el = document.getElementById(id)
if (el.style.display !== 'none')
el.style.display = 'none'
else
el.style.display = ''
}
console.log('syntax looks right')
</script>
</body>
</html>
================================================
FILE: docs/index.md
================================================
<script>window.location.replace('https://github.com/Artoria2e5/PRCoords/')</script>
<script>window.location.href = 'https://github.com/Artoria2e5/PRCoords/'</script>
Just go to the <a href="https://github.com/Artoria2e5/PRCoords">GitHub repo</a>.
================================================
FILE: docs/proj4_plugin.js
================================================
// mirror of https://runkit.com/artoria2e5/proj4-plugin-prcoords
const proj4 = require("proj4")
const prcoords = require("prcoords")
const noop = Function.prototype
const DEG = Math.PI / 180
function xy_to_ll(p) {
return { lon: p.x / DEG, lat: p.y / DEG }
}
function ll_to_xy(p) {
return { x: p.lon * DEG, y: p.lat * DEG }
}
function xy_rename_ll(p) {
return { lon: p.x, lat: p.y }
}
function ll_rename_xy(p) {
return { x: p.lon, y: p.lat }
}
function wrap(f, ...args) {
return (p) => ll_to_xy(f(xy_to_ll(p), ...args))
}
// We lie our way to Baidu "Mercator".
proj4.defs([
[
"_CLARK_MC",
"+proj=merc +a=6378206.4 +b=6356583.8 +lat_ts=0.0 +lon_0=0.0 +x_0=0 +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs",
],
["_CLARK_LL", "+proj=longlat +a=6378206.4 +b=6356583.8"],
])
proj4.Proj.projections.add({
init: noop,
forward: wrap(prcoords.wgs_gcj),
inverse: wrap(prcoords.gcj_wgs_bored),
names: ["gcj", "gcj02", "CN_Obfs_GCJ_2002_Ellipsoidal"],
})
proj4.Proj.projections.add({
init: noop,
forward: wrap(prcoords.wgs_bd),
inverse: wrap(prcoords.bd_wgs_bored),
names: ["baidu", "bd09", "CN_Obfs_Baidu_2009_Ellipsoidal"],
})
proj4.Proj.projections.add({
init: noop,
forward: (p) =>
proj4("_CLARK_LL", "_CLARK_MC", ll_rename_xy(prcoords.wgs_bd(xy_to_ll(p)))),
inverse: (p) =>
ll_to_xy(
prcoords.bd_wgs_bored(xy_rename_ll(proj4("_CLARK_MC", "_CLARK_LL", p))),
),
names: ["baidu", "bd09mc", "CN_Obfs_Baidu_2009_Mercator"],
})
proj4.defs([
// Why isn't units=degrees working... work around with wrap() now.
["GCJ02", "+title=GCJ 02 (long/lat) +proj=gcj02 +units=degrees"],
["BD09", "+title=Baidu 2009 (long/lat) +proj=bd09 +units=degrees"],
["BD09MC", "+title=Baidu 2009 (Mercator) +proj=bd09mc +units=m"],
])
console.log([
// should be the same as https://artoria2e5.github.io/PRCoords/demo
xy_to_ll(proj4("WGS84", "BD09", { x: 105, y: 35 })),
xy_to_ll(proj4("WGS84", "GCJ02", { x: 105, y: 35 })),
])
console.log([
// should be very close to the original
proj4(
"BD09",
"WGS84",
ll_to_xy({ lat: 35.005403668456964, lon: 105.00966682831948 }),
),
proj4(
"GCJ02",
"WGS84",
ll_to_xy({ lat: 34.99909863223526, lon: 105.00328624145706 }),
),
])
console.log([
proj4("WGS84", "BD09MC", { x: 105, y: 35 }),
proj4("BD09MC", "WGS84", { x: 11689750, y: 4139877 }),
])
================================================
FILE: haskell/PRCoords.cabal
================================================
-- Initial prcoords.cabal generated by cabal init. For further
-- documentation, see http://haskell.org/cabal/users-guide/
-- The name of the package.
name: PRCoords
-- The package version. See the Haskell package versioning policy (PVP)
-- for standards guiding when and how versions should be incremented.
-- http://www.haskell.org/haskellwiki/Package_versioning_policy
-- PVP summary: +-+------- breaking API changes
-- | | +----- non-breaking API additions
-- | | | +--- code changes with no API change
version: 0.1.0.0
-- A short (one-line) description of the package.
synopsis: Library for GCJ-02 and BD-09 (de)obfuscation from/to WGS-84. May trigger mental episodes.
description: People's Rectified Coordinates (PRCoords) is a cross-language implementation of "public secret" Chinese coordinate obfuscation methods including GCJ-02 and BD-09, along with general deobfuscation methods previously established in pycoordtrans, eviltransform, and geoChina.
-- URL for the project homepage or repository.
homepage: https://github.com/Artoria2e5/PRCoords
-- The license under which the package is released.
license: PublicDomain
-- The file containing the license text.
-- license-file: LICENSE
-- The package author(s).
author: Mingye Wang
-- An email address to which users can send suggestions, bug reports, and
-- patches.
maintainer: arthur200126@gmail.com
-- A copyright notice.
-- copyright:
category: Geography
build-type: Simple
-- Extra files to be distributed with the package, such as examples or a
-- README.
-- extra-source-files:
-- Constraint on the version of Cabal needed to build this package.
cabal-version: >=1.10
library
-- Modules exported by the library.
exposed-modules: PRCoords
-- Modules included in this library but not exported.
-- other-modules:
-- LANGUAGE extensions used by modules in this package.
other-extensions: BangPatterns
-- Other library packages from which modules are imported.
build-depends:
base -- >=4.8 && <4.9
-- AC-Angle
-- Directories containing source files.
-- hs-source-dirs:
-- Base language which the package is written in.
default-language: Haskell2010
================================================
FILE: haskell/PRCoords.hs
================================================
{-# LANGUAGE BangPatterns #-}
{-# OPTIONS_GHC -fexcess-precision #-}
{-# OPTIONS_GHC -optc-ffast-math -optllc--enable-unsafe-fp-math -optllc--enable-no-nans-fp-math -optllc--enable-no-infs-fp-math #-}
--- | This module contains functions for generating People's Rectified Coordinates.
--- Jeez, my naming is awful.
module PRCoords where -- (wgsGcj, gcjBd, wgsBd, gcjWgs, bdGcj, bdWgsC, gcjWgsC, bdGcjC, bdWgsC, caijun)
-- import Data.Angle
-- import Numeric.FastMath
data PCoords = PCoords { !lat :: Double
, !lon :: Double } deriving (Eq, Ord, Show)
subtractPCoords :: PCoords -> PCoords -> PCoords
subtractPCoords a b = PCoords (lat a - lat b) (lon a - lon b)
wgsGcj :: PCoords -> PCoords
wgsGcj (PCoords lat lon) = PCoords (lat + dLat / arclenLat) (lon + dLon / arclenLon) where
gcj_a = 6378245.0 -- <_ Krasovsky 1940
gcj_ee = 0.00669342162296594323 -- f = 1/2983; e^2 = 2*f - f**2
magic = 1 - gcj_ee * ((sin (pi * lat / 180)) ** 2) -- common expr
arclenLat = (pi / 180) * (gcj_a * (1 - gcj_ee)) / (magic ** 1.5)
arclenLon = (pi / 180) * (gcj_a * (cos (pi * lat / 180)) / (sqrt magic))
x = lon - 105 -- Here goes the deviation
y = lat - 35
gcjTerm !v !f !n = n * (sin f * v * pi)
-- check operator stuff later
dLat = -100 + 2 * x + 3 * y + 0.2 * y ** 2 + 0.1 * x * y + 0.2 * (sqrt (abs x)) + (*) (20/3) (
gcjTerm x 6 2 + gcjTerm x 2 2 + gcjTerm y 1 2 + gcjTerm y (1/3) 4 +
gcjTerm y (1/12) 16 + gcjTerm y (1/30) 32)
dLon = 300 + 1 * x + 2 * y + 0.1 * x ** 2 + 0.1 * x * y + 0.1 * (sqrt (abs x)) + (*) (20/3) (
gcjTerm x 6 2 + gcjTerm x 2 2 + gcjTerm x 1 2 + gcjTerm x (1/3) 4 +
gcjTerm x (1/12) 15 + gcjTerm y (1/30) 30)
gcjWgs :: PCoords -> PCoords
gcjWgs a = subtractPCoords a (subtractPCoords ga a) where
ga = wgsGcj a
caiFix :: (PCoords -> PCoords) -> PCoords -> PCoords -> Int -> PCoords
caiFix fwd guess fwd_result iter
| iter > 5 = better
| (abs $ lon diff) + (abs $ lat diff) < 1E-5 = better
| otherwise = caiFix fwd better fwd_result (iter+1)
where fwd_guess = fwd guess
diff = subtractPCoords fwd_guess fwd_result
better = subtractPCoords guess diff
caijun :: (PCoords -> PCoords) -> (PCoords -> PCoords) -> (PCoords -> PCoords)
caijun fwd rev = (\x -> caiFix fwd (rev x) x 0)
gcjWgsC :: PCoords -> PCoords
gcjWgsC = caijun wgsGcj gcjWgs
-- next: baidu
================================================
FILE: haskell/Setup.hs
================================================
import Distribution.Simple
main = defaultMain
================================================
FILE: js/.npmignore
================================================
misc
================================================
FILE: js/PRCoords.d.ts
================================================
// Type definitions for PRCoords
// Project: PRCoords
export as namespace PRCoords
export interface PRCoord {
lat: number
lon: number
}
export type PRCoordOp = (c: PRCoord, checkChina?: boolean) => PRCoord
export function distance(a: PRCoord, b: PRCoord): number
// We do not use the PRCO type to make it a bit more transparent on the IDE
export function gcj_wgs(c: PRCoord, checkChina?: boolean): PRCoord
export function wgs_gcj(c: PRCoord, checkChina?: boolean): PRCoord
export function wgs_gcj_bored(c: PRCoord, checkChina?: boolean): PRCoord
export function gcj_bd(c: PRCoord, __dummy__?: boolean): PRCoord
export function bd_gcj(c: PRCoord, __dummy__?: boolean): PRCoord
export function bd_gcj_bored(c: PRCoord, __dummy__?: boolean): PRCoord
export function wgs_bd(c: PRCoord, checkChina?: boolean): PRCoord
export function bd_wgs(c: PRCoord, checkChina?: boolean): PRCoord
export function bd_wgs_bored(c: PRCoord, checkChina?: boolean): PRCoord
export function __bored__(fwd: PRCoordOp, rev: PRCoordOp): PRCoordOp
================================================
FILE: js/PRCoords.js
================================================
;(function (factory, scope) {
"use strict"
var res = factory()
if (typeof module === 'object') {
module.exports = res
} else {
if (typeof define === 'function' && define.amd)
define('prcoords', function() { return res })
try {
// Global can be undefined
scope.PRCoords = res
} catch(e) {}
}
})((function (){
"use strict"
// <nowiki>
/**
* People's Rectified Coordinates
* @file Utils for inserting valid WGS-84 coords from GCJ-02/BD-09 input
* @author User:Artoria2e5
* @url https://github.com/Artoria2e5/PRCoords
*
* @see [[:en:GCJ-02]]
* @see https://en.wikipedia.org/wiki/User:Artoria2e5/coord-notice
* @see https://github.com/caijun/geoChina (GPLv3)
* @see https://github.com/googollee/eviltransform (MIT)
* @see https://on4wp7.codeplex.com/SourceControl/changeset/view/21483#353936 (Anonymous)
* @see https://github.com/zxteloiv/pycoordtrans (BSD-3)
*
* @license CC0
* To the greatest extent possible, this implementation of obfuscations designed
* in hope that they will screw y'all up is dedicated into the public domain
* under CC0 1.0 <https://creativecommons.org/publicdomain/zero/1.0/>.
*
* Happy geotagging/ingressing/whatever.
*
* To make my FSF membership shine brighter, this conversion implementation is
* additionally licensed under GPLv3+:
* @license GPLv3+
* @copyright 2016 Mingye Wang (User:Artoria2e5)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/// Krasovsky 1940 ellipsoid
/// @const
var GCJ_A = 6378245
var GCJ_EE = 0.00669342162296594323 // f = 1/298.3; e^2 = 2*f - f**2
/// Epsilon to use for "exact" iterations.
/// Wanna troll? Use Number.EPSILON. 1e-13 in 15 calls for gcj.
/// @const
var PRC_EPS = 1e-5
/// Baidu's artificial deviations
/// @const
var BD_DLAT = 0.0060
var BD_DLON = 0.0065
/// Mean Earth Radius
/// @const
var EARTH_R = 6371000
/// Distance for haversine method; suitable over short distances like
/// conversion deviation checking
function distance(a, b) {
function hav(θ) {
return Math.pow(Math.sin(θ/2), 2)
}
var Δ = _coord_diff(a, b)
return 2 * EARTH_R * Math.asin(Math.sqrt(
hav(Δ.lat * Math.PI / 180) +
Math.cos(a.lat * Math.PI / 180) *
Math.cos(b.lat * Math.PI / 180) *
hav(Δ.lon * Math.PI / 180)
))
}
function sanity_in_china_p(coords) {
return coords.lat >= 0.8293 && coords.lat <= 55.8271 &&
coords.lon >= 72.004 && coords.lon <= 137.8347
}
function _coord_diff(a, b) {
return {
lat: a.lat - b.lat,
lon: a.lon - b.lon,
}
}
function _stringify(c) {
return "(" + c.lat + ", " + c.lon + ")"
}
function wgs_gcj(wgs, checkChina) {
if ((checkChina === undefined || checkChina) && !sanity_in_china_p(wgs)) {
console.warn("Non-Chinese coords found, returning as-is: " +
_stringify(wgs))
return wgs
}
var x = wgs.lon - 105, y = wgs.lat - 35
// These distortion functions accept (x = lon - 105, y = lat - 35).
// They return distortions in terms of arc lengths, in meters.
//
// In other words, you can pretty much figure out how much you will be off
// from WGS-84 just through evaulating them...
//
// For example, at the (mapped) center of China (105E, 35N), you get a
// default deviation of <300, -100> meters.
var dLat_m = -100 + 2 * x + 3 * y + 0.2 * y * y + 0.1 * x * y +
0.2 * Math.sqrt(Math.abs(x)) + (
2 * Math.sin(x * 6 * Math.PI) + 2 * Math.sin(x * 2 * Math.PI) +
2 * Math.sin(y * Math.PI) + 4 * Math.sin(y / 3 * Math.PI) +
16 * Math.sin(y / 12 * Math.PI) + 32 * Math.sin(y / 30 * Math.PI)
) * 20 / 3
var dLon_m = 300 + x + 2 * y + 0.1 * x * x + 0.1 * x * y +
0.1 * Math.sqrt(Math.abs(x)) + (
2 * Math.sin(x * 6 * Math.PI) + 2 * Math.sin(x * 2 * Math.PI) +
2 * Math.sin(x * Math.PI) + 4 * Math.sin(x / 3 * Math.PI) +
15 * Math.sin(x / 12 * Math.PI) + 30 * Math.sin(x / 30 * Math.PI)
) * 20 / 3
var radLat = wgs.lat / 180 * Math.PI
var magic = 1 - GCJ_EE * Math.pow(Math.sin(radLat), 2) // just a common expr
// [[:en:Latitude#Length_of_a_degree_of_latitude]]
var lat_deg_arclen = (Math.PI / 180) * (GCJ_A * (1 - GCJ_EE)) / Math.pow(magic, 1.5)
// [[:en:Longitude#Length_of_a_degree_of_longitude]]
var lon_deg_arclen = (Math.PI / 180) * (GCJ_A * Math.cos(radLat) / Math.sqrt(magic))
// The screwers pack their deviations into degrees and disappear.
// Note how they are mixing WGS-84 and Krasovsky 1940 ellipsoids here...
return {
lat: wgs.lat + (dLat_m / lat_deg_arclen),
lon: wgs.lon + (dLon_m / lon_deg_arclen),
}
}
// rev_transform_rough; accuracy ~2e-6 deg (meter-level)
function gcj_wgs(gcj, checkChina) {
return _coord_diff(gcj, _coord_diff(wgs_gcj(gcj, checkChina), gcj))
}
function gcj_bd(gcj, __dummy__) {
var x = gcj.lon
var y = gcj.lat
// trivia: pycoordtrans actually describes how these values are calculated
var r = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * Math.PI * 3000 / 180)
var θ = Math.atan2(y, x) + 0.000003 * Math.cos(x * Math.PI * 3000 / 180)
// Hard-coded default deviations again!
return {
lat: r * Math.sin(θ) + BD_DLAT,
lon: r * Math.cos(θ) + BD_DLON,
}
}
// Yes, we can implement a "precise" one too.
// accuracy ~1e-7 deg (decimeter-level; exceeds usual data accuracy)
function bd_gcj(bd, __dummy__) {
var x = bd.lon - BD_DLON
var y = bd.lat - BD_DLAT
// trivia: pycoordtrans actually describes how these values are calculated
var r = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * Math.PI * 3000 / 180)
var θ = Math.atan2(y, x) - 0.000003 * Math.cos(x * Math.PI * 3000 / 180)
return {
lat: r * Math.sin(θ),
lon: r * Math.cos(θ),
}
}
function bd_wgs(bd, checkChina) {
return gcj_wgs(bd_gcj(bd), checkChina)
}
function wgs_bd(bd, checkChina) {
return gcj_bd(wgs_gcj(bd, checkChina))
}
// generic "bored function" factory, Caijun 2014
// gcj: 4 calls to wgs_gcj; ~0.1mm acc
function __bored__(fwd, rev) {
return function rev_bored(heck, checkChina) {
if (checkChina === undefined) checkChina = true
var curr = rev(heck, checkChina)
var diff = {lat: Infinity, lon: Infinity}
// Wait till we hit fixed point or get bored
var i = 0
while (Math.max(Math.abs(diff.lat), Math.abs(diff.lon)) > PRC_EPS && i++ < 10) {
diff = _coord_diff(fwd(curr, checkChina), heck)
curr = _coord_diff(curr, diff)
}
return curr
}
}
var exports = {
distance: distance,
wgs_gcj: wgs_gcj,
gcj_wgs: gcj_wgs,
gcj_bd: gcj_bd,
bd_gcj: bd_gcj,
wgs_bd: wgs_bd,
bd_wgs: bd_wgs,
// Precise functions using caijun 2014 method
//
// Why "bored"? Because they usually exceed source data accuracy -- the
// original GCJ implementation contains noise from a linear-modulo PRNG,
// and Baidu seems to do similar things with their API too.
__bored__: __bored__,
gcj_wgs_bored: __bored__(wgs_gcj, gcj_wgs),
bd_gcj_bored: __bored__(gcj_bd, bd_gcj),
bd_wgs_bored: __bored__(wgs_bd, bd_wgs),
}
// We can stub this out too if we are aiming for ES3, but then there are no
// trailing commas
Object.defineProperty(exports, '__esModule', { value: true })
return exports
}), typeof self !== 'undefined' ? self : typeof this !== undefined ? this : globalThis)
================================================
FILE: js/misc/insane_is_in_china.js
================================================
(function(){
"use strict"
// Insane version of the "is in China" check (70 points. I tried.)
//
// Dedicated to the Public Domain under CC0, except for pnpoly by
// Wm. Randolph Franklin (BSD3)
//
// Incorrect use of this polygon can lead to adverse geopolitical issues.
// This set of points is only intended to approximate the scope of a type of distortion,
// and has nothing to do with any political entities.
//
// Also, screw geodetics. The Earth is flat according to this approximation.
/// *** pnpoly *** ///
// Copyright (c) 1970-2003, Wm. Randolph Franklin
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimers.
// 2. Redistributions in binary form must reproduce the above
// copyright notice in the documentation and/or other materials
// provided with the distribution.
// 3. The name of W. Randolph Franklin may not be used to endorse or
// promote products derived from this Software without specific
// prior written permission.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
function pnpoly(xs, ys, x, y) {
if (! (xs.length === ys.length))
throw new Error("pnpoly: assert(xs.length === ys.length)")
var inside = 0
// j records previous value. Also handles wrapping around.
for (let i = 0, j = xs.length - 1; i < xs.length; j = i++)
inside ^= (((ys[i] > y) !== (ys[j] > y)) &&
(x < (xs[j] - xs[i]) * (y - ys[i]) / (ys[j] - ys[i]) + xs[i]))
// Let's make js as magical as C. Yay.
return !!inside
}
/// ^^^ pnpoly ^^^ ///
// We will need to filter out these points for Baidu.
// (We will need South China Sea too.)
var is_near_hkmo = function (lat, lon) {
return 22 <= lat && lat <= 22.7 && 113.5 <= lon && lon <= 114.5
}
// Well we now have indices for HK/MO.
var HK_LENGTH = 12
// lon, lat
var POINTS = [
// start hkmo
114.433722, 22.064310,
114.009458, 22.182105,
113.599275, 22.121763,
113.583463, 22.176002,
113.530900, 22.175318,
113.529542, 22.210608,
113.613377, 22.227435,
113.938514, 22.483714,
114.043449, 22.500274,
114.138506, 22.550640,
114.222984, 22.550960,
114.366803, 22.524255,
// end hkmo
115.254019, 20.235733,
121.456316, 26.504442,
123.417261, 30.355685,
124.289197, 39.761103,
126.880509, 41.774504,
127.887261, 41.370015,
128.214602, 41.965359,
129.698745, 42.452788,
130.766139, 42.668534,
131.282487, 45.037051,
133.142361, 44.842986,
134.882453, 48.370596,
132.235531, 47.785403,
130.980075, 47.804860,
130.659026, 48.968383,
127.860252, 50.043973,
125.284310, 53.667091,
120.619316, 53.100485,
119.403751, 50.105903,
117.070862, 49.690388,
115.586019, 47.995542,
118.599613, 47.927785,
118.260771, 46.707335,
113.534759, 44.735134,
112.093739, 45.001999,
111.431259, 43.489381,
105.206324, 41.809510,
96.485703, 42.778692,
94.167961, 44.991668,
91.130430, 45.192938,
90.694601, 47.754437,
87.356293, 49.232005,
85.375791, 48.263928,
85.876055, 47.109272,
82.935423, 47.285727,
81.929808, 45.506317,
79.919457, 45.108122,
79.841455, 42.178752,
73.334917, 40.076332,
73.241805, 39.062331,
79.031902, 34.206413,
78.738395, 31.578004,
80.715812, 30.453822,
81.821692, 30.585965,
85.501663, 28.208463,
92.096061, 27.754241,
94.699781, 29.357171,
96.079442, 29.429559,
98.910308, 27.140660,
97.404057, 24.494701,
99.400021, 23.168966,
100.697449, 21.475914,
102.976870, 22.616482,
105.476997, 23.244292,
108.565621, 20.907735,
107.730505, 18.193406,
110.669856, 17.754550,
]
var lats = POINTS.filter((ditch, i) => i % 2 == 1)
var lons = POINTS.filter((ditch, i) => i % 2 == 0)
POINTS = null // no need
var bdlats = lats.slice(HK_LENGTH)
var bdlons = lons.slice(HK_LENGTH)
function isInGoogle(lat, lon) {
// Yank out South China Sea
if (lat <= 17.75455)
return false;
return pnpoly(lats, lons, lat, lon)
}
function isInBaidu(lat, lon) {
// Yank out South China Sea, as:
// 1. Nobody wants Baidu's crap Sansha data
// 2. I am too lazy to add like four points
if (lat <= 17.75455)
return false;
return pnpoly(bdlats, bdlons, lat, lon)
}
exports = {isInBaidu: isInBaidu, isInGoogle: isInGoogle}
if (typeof module === "object" && module.exports) {
module.exports = exports
} else if (typeof window !== "undefined") {
window.PRCoords = exports
}
})()
================================================
FILE: js/misc/package.json
================================================
{
"name": "insane-in-china",
"version": "0.0.1",
"description": "Routine for deciding whether one coordiate might be affected by Chinese obfuscation.",
"main": "insane_is_in_china.js",
"repository": {
"type": "git",
"url": "https://github.com/Artoria2e5/PRCoords.git",
"directory": "js/misc"
},
"keywords": [
"gcj", "wgs", "bd", "baidu", "coordinates", "pnpoly"
],
"author": "Mingye Wang (Artoria2e5) <arthur200126@gmail.com>",
"license": "BSD-3-Clause",
"bugs": {
"url": "https://github.com/Artoria2e5/PRCoords/issues"
}
}
================================================
FILE: js/package.json
================================================
{
"name": "prcoords",
"version": "1.0.3-rc1",
"description": "Chinese coordinate obfuscation methods (GCJ-02, BD-09) and inverses.",
"main": "PRCoords.js",
"repository": {
"type": "git",
"url": "https://github.com/Artoria2e5/PRCoords.git",
"directory": "js",
"//note": "Unused before I figure out what to do with docs and readme."
},
"keywords": [
"gcj",
"wgs",
"bd",
"baidu",
"coordinates"
],
"author": "Mingye Wang (Artoria2e5) <arthur200126@gmail.com>",
"license": "CC0-1.0",
"bugs": {
"url": "https://github.com/Artoria2e5/PRCoords/issues"
},
"dependencies": {}
}
================================================
FILE: julia/Project.toml
================================================
name = "PRCoords"
uuid = "0c59880a-3f55-4b0d-8a02-bd83932d11da"
authors = ["Mingye Wang <arthur2e5@aosc.io>"]
version = "0.1.0"
================================================
FILE: julia/src/PRCoords.jl
================================================
module PRCoords
struct Coords
lat::Float64
lon::Float64
end
end # module
================================================
FILE: lua/PRCoords.lua
================================================
-- People's Rectified Coordinates
-- https://github.com/Artoria2e5/PRCoords
--
-- Dedicated to the Public Domain under CC0
-- Artoria2e5, 2017.
PRCoords = {
["EARTH_R"] = 6371000
}
-- Ray-casting polygon
function PRCoords._in_poly(xs, ys, x, y)
assert(#xs == #ys, "poly length don't match")
local inside = false
for i=1,#xs do
if (ys[i] > y) ~= (ys[j] > y) and
(x < (xs[j] - xs[i]) * (y - ys[i]) / (ys[j] - ys[i]) + xs[i]) then
inside = (not inside)
end
end
return inside
end
local function bind_poly(xs, ys)
return function(x, y)
return PRCoords._in_poly(xs, ys, x, y)
end
end
function PRCoords.cdiff(a_lat, a_lon, b_lat, b_lon)
return a_lat - b_lat, a_lon - b_lon
end
local function cerr(lat, lon)
return abs(lat) + abs(lon)
end
function PRCoords.cdist(a_lat, a_lon, b_lat, b_lon)
local function hav(theta)
return math.sin(theta/2) ^ 2
end
local delta_lat = a_lat - b_lat
local delta_lon = a_lon - b_lon
return 2 * PRCoords.EARTH_R * math.asin(math.sqrt(
hav(delta_lat * math.pi / 180) +
math.cos(a.lat * math.pi / 180) *
math.cos(b.lat * math.pi / 180) *
hav(delta_lon * math.pi / 180)))
end
function PRCoords.caijun(forward, reverse)
return function(bad_lat, bad_lon)
local guess_lat, guess_lon = reverse(bad_lat, bad_lon)
local iter = 0
local diff_lat, diff_lon, tlat, tlon
repeat
tlat, tlon = forward(guess_lat, guess_lon)
diff_lat, diff_lon = PRCoords.cdiff(tlat, tlon, bad_lat, bad_lon)
guess_lat -= diff_lat
guess_lon -= diff_lon
iter += 1
until cerr(diff_lat, diff_lon) <= 1e-5 or iter >= 10
end
end
function PRCoords.wgs_gcj(wlat, wlon)
local y, x = wlon - 105, wlat - 35
end
================================================
FILE: matlab/PRCoords.m
================================================
function v = PRCoords()
%% People's Rectified Coordinates: Chinese geographic obfuscations
%% Dedicated to the Public Domain under CC0.
%% Mingye Wang (Artoria2e5), 2017, 2025.
%% @url https://github.com/Artoria2e5/PRCoords
v = "1.2.0";
end
================================================
FILE: matlab/bd_gcj.m
================================================
function g = bd_gcj (b)
% Reverse the BD-09 distortion to GCJ-02 coordinates.
x = b (2) - 0.0065;
y = b (1) - 0.006;
r = sqrt (x .* x + y .* y) - 0.00002 * sin (y * pi * 3000 / 180);
theta = atan2 (y, x) - 0.000003 * cos (x * pi * 3000 / 180);
gcj_lon = r .* cos (theta);
gcj_lat = r .* sin (theta);
g = [gcj_lat, gcj_lon];
endfunction
================================================
FILE: matlab/bd_gcj_precise.m
================================================
function g = bd_gcj_precise (b, tol, maxn)
% Reverse the BD-09 distortion to GCJ-02 coordinates in a precise way.
if nargin < 2
tol = 1e-13;
end
if nargin < 3
maxn = 10;
end
fun = caijun_precise (@gcj_bd, @bd_gcj);
g = fun (b, tol, maxn);
endfunction
================================================
FILE: matlab/bd_wgs.m
================================================
function w = bd_wgs (b)
% Reverse the BD-09 distortion to WGS-84 coordinates.
g = bd_gcj (b);
w = gcj_wgs (g);
endfunction
================================================
FILE: matlab/bd_wgs_precise.m
================================================
function w = bd_wgs_precise (b, tol, maxn)
% Reverse the BD-09 distortion to WGS-84 coordinates in a precise way.
if nargin < 2
tol = 1e-13;
end
if nargin < 3
maxn = 10;
end
fun = caijun_precise (@wgs_bd, @bd_wgs);
w = fun (b, tol, maxn);
endfunction
================================================
FILE: matlab/caijun_precise.m
================================================
function fun = caijun_precise (fwd, rev, o, tol, maxn)
% usage: fun = caijun_precise (@fwd, @rev)
%
% With a precise forward obfuscation and a rough deobfuscation
% function, construct a precise iterative deobfuscation function.
%
% A custom tolilon for "fixed point" detection can be specified
% with the "tol" operand. The default value is 1e-4 degrees.
%
% A custon max iteration limit can be specified with the "maxn"
% operand. The default value is 10 iterations.
%
% (caijun/geoChina; 2014)
function c = rectify (o, tol, maxn)
% Given obfuscated coords,
% return something that appears much less wrong to us.
c = rev (o);
d = c - o;
for i = 1:maxn
if (max(abs(d (1))) + max(abs(d (2))) <= tol)
break;
end
d = fwd(c) - o;
c -= d;
end
endfunction
fun = @rectify;
endfunction
================================================
FILE: matlab/gcj_bd.m
================================================
function b = gcj_bd (g)
% Apply the BD-09 distortion to GCJ-02 coordinates.
x = g (2);
y = g (1);
r = sqrt (x .* x + y .* y) + 0.00002 * sin (y * pi * 3000 / 180);
theta = atan2 (y, x) + 0.000003 * cos (x * pi * 3000 / 180);
bd_lon = r .* cos (theta) + 0.0065;
bd_lat = r .* sin (theta) + 0.006;
b = [bd_lat, bd_lon];
endfunction
================================================
FILE: matlab/gcj_wgs.m
================================================
function w = gcj_wgs (g)
% Reverse the GCJ-02 distortion in a rough way.
gg = wgs_gcj (g);
w = g * 2 - gg;
endfunction
================================================
FILE: matlab/gcj_wgs_precise.m
================================================
function w = gcj_wgs_precise (g, tol, maxn)
if nargin < 2
tol = 1e-13;
end
if nargin < 3
maxn = 10;
end
fun = caijun_precise (@wgs_gcj, @gcj_wgs);
w = fun (g, tol, maxn);
endfunction
================================================
FILE: matlab/wgs_bd.m
================================================
function b = wgs_bd (w)
% Apply the BD-09 distortion to WGS-84 coordinates.
g = wgs_gcj (w);
b = gcj_bd (g);
endfunction
================================================
FILE: matlab/wgs_gcj.m
================================================
function r = wgs_gcj (w)
% Apply the GCJ-02 distortion to WGS-84 coordinates.
wlat = w (1); wlon = w (2);
% Krasovsky 1940 ellipsoid
GCJ_A = 6378245;
GCJ_EE = 0.00669342162296594323; % f = 1./298.3; e^2 = 2.*f - f.*.*2
% Deviation computation in meters, inlined.
% [x, y] are relative coords from a common mapped "center" of China.
x = wlat - 35;
y = wlon - 105;
dlat = -100 + 2 .* x + 3 .* y + 0.2 .* y .* y + 0.1 .* x .* y + ...
0.2 .* sqrt(abs(x)) + (2 .* sin(x .* 6 .* pi) + ...
2 .* sin(x .* 2 .* pi) + 2 .* sin(y .* pi) + 4 .* sin(y ./ 3 .* pi) + ...
16 .* sin(y ./ 12 .* pi) + 32 .* sin(y ./ 30 .* pi)) .* 20 ./ 3;
dlon = 300 + x + 2 .* y + 0.1 .* x .* x + 0.1 .* x .* y + ...
0.1 .* sqrt(abs(x)) + (2 .* sin(x .* 6 .* pi) + ...
2 .* sin(x .* 2 .* pi) + 2 .* sin(x .* pi) + 4 .* sin(x ./ 3 .* pi) + ...
15 .* sin(x ./ 12 .* pi) + 30 .* sin(x ./ 30 .* pi)) .* 20 ./ 3;
% Arc lengths for one degree on the wrong ellipsoid
magic = 1 - GCJ_EE .* (sind(wlat) .^ 2); % A common expression
arclen_1lat = pi / 180 .* (GCJ_A .* (1 - GCJ_EE)) ./ magic .^ 1.5;
arclen_1lon = pi / 180 .* GCJ_A .* cosd(wlat) ./ magic .^ 0.5;
% Pack deviations into degrees
glat = wlat + dlat ./ arclen_1lat;
glon = wlon + dlon ./ arclen_1lon;
r = [glat, glon];
endfunction
================================================
FILE: package.json
================================================
{
"name": "prcoords",
"version": "1.0.5",
"description": "Chinese coordinate obfuscation methods (GCJ-02, BD-09) and inverses.",
"main": "js/PRCoords.js",
"//": "Will this work with the repo? https://github.com/npm/npm/issues/2974",
"repository": "github:Artoria2e5/PRCoords",
"keywords": [
"gcj",
"wgs",
"bd",
"baidu",
"coordinates"
],
"author": "Mingye Wang (Artoria2e5) <arthur200126@gmail.com>",
"license": "CC0-1.0",
"bugs": {
"url": "https://github.com/Artoria2e5/PRCoords/issues"
},
"dependencies": {}
}
================================================
FILE: pgsql/distance_agg.sql
================================================
CREATE TYPE _geodistance_agg_state AS
(distance double precision, lat double precision, lon double precision);
CREATE FUNCTION public._geodistance_agg_sfunc
(state _geodistance_agg_state, lat double precision, lon double precision)
RETURNS _geodistance_agg_state AS $$
SELECT
(CASE WHEN $1 IS NULL THEN 0
ELSE $1.distance+geodistance($1.lat, $1.lon, $2, $3) END),
$2, $3
AS nextstate;
$$ LANGUAGE SQL IMMUTABLE;
CREATE FUNCTION public._geodistance_agg_ffunc (state _geodistance_agg_state)
RETURNS double precision AS $$
SELECT $1.distance AS result;
$$ LANGUAGE SQL IMMUTABLE;
CREATE AGGREGATE geodistance_agg (double precision, double precision) (
SFUNC = _geodistance_agg_sfunc,
STYPE = _geodistance_agg_state,
FINALFUNC = _geodistance_agg_ffunc
);
================================================
FILE: pgsql/prcoords.sql
================================================
CREATE OR REPLACE FUNCTION public.geodistance
(alat double precision, alng double precision, blat double precision, blng double precision)
RETURNS double precision AS $$
SELECT 2 * 6371000 * asin(
sqrt(
sin(radians($3-$1)/2)^2 +
sin(radians($4-$2)/2)^2 * cos(radians($1)) * cos(radians($3))
)
) AS distance;
$$ LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE COST 100;
CREATE OR REPLACE FUNCTION public.geodistance (a point, b point)
RETURNS double precision AS $$
SELECT 2 * 6371000 * asin(
sqrt(
sin(radians($2[0]-$1[0])/2)^2 +
sin(radians($2[1]-$1[1])/2)^2 * cos(radians($1[0])) * cos(radians($2[0]))
)
) AS distance;
$$ LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE COST 100;
CREATE OR REPLACE FUNCTION public.wgs_gcj (wgs point) RETURNS point AS
$$
DECLARE
GCJ_A CONSTANT double precision := 6378245;
GCJ_EE CONSTANT double precision := 0.00669342162296594323;
x double precision;
y double precision;
dLat_m double precision;
dLon_m double precision;
radLat double precision;
magic double precision;
lat_deg_arclen double precision;
lon_deg_arclen double precision;
BEGIN
x := wgs[1] - 105;
y := wgs[0] - 35;
dLat_m := (-100 + 2 * x + 3 * y + 0.2 * y * y + 0.1 * x * y +
0.2 * sqrt(abs(x)) + (
2 * sin(x * 6 * pi()) + 2 * sin(x * 2 * pi()) +
2 * sin(y * pi()) + 4 * sin(y / 3 * pi()) +
16 * sin(y / 12 * pi()) + 32 * sin(y / 30 * pi())
) * 20 / 3);
dLon_m := (300 + x + 2 * y + 0.1 * x * x + 0.1 * x * y +
0.1 * sqrt(abs(x)) + (
2 * sin(x * 6 * pi()) + 2 * sin(x * 2 * pi()) +
2 * sin(x * pi()) + 4 * sin(x / 3 * pi()) +
15 * sin(x / 12 * pi()) + 30 * sin(x / 30 * pi())
) * 20 / 3);
radLat := radians(wgs[0]);
magic := 1 - GCJ_EE * power(sin(radLat), 2);
lat_deg_arclen := radians((GCJ_A * (1 - GCJ_EE)) / power(magic, 1.5));
lon_deg_arclen = radians(GCJ_A * cos(radLat) / sqrt(magic));
RETURN (wgs[0] + (dLat_m / lat_deg_arclen),
wgs[1] + (dLon_m / lon_deg_arclen));
END;
$$ LANGUAGE plpgsql IMMUTABLE STRICT PARALLEL SAFE COST 150;
CREATE OR REPLACE FUNCTION public.gcj_wgs (gcj point) RETURNS point AS $$
SELECT $1 - (wgs_gcj($1) - $1) AS wgs
$$ LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE COST 150;
CREATE OR REPLACE FUNCTION public.gcj_wgs_bored (gcj point) RETURNS point AS
$$
DECLARE
MAXITER CONSTANT double precision := 10;
PRC_EPS CONSTANT double precision := 1e-5;
wgs point;
old point;
diff point;
i smallint;
BEGIN
wgs = gcj_wgs(gcj);
LOOP
diff := (wgs - old);
IF i < MAXITER AND (abs(diff[0]) > PRC_EPS OR abs(diff[1]) > PRC_EPS) THEN
old := wgs;
wgs := wgs - (wgs_gcj(wgs) - gcj);
i := i + 1;
ELSE
RETURN wgs;
END IF;
END LOOP;
END;
$$ LANGUAGE plpgsql IMMUTABLE STRICT PARALLEL SAFE COST 450;
CREATE OR REPLACE FUNCTION public.gcj_bd (gcj point) RETURNS point AS
$$
DECLARE
r double precision;
t double precision;
BEGIN
r := sqrt(gcj[0] * gcj[0] + gcj[1] * gcj[1]) + 2e-5 * sin(3000 * radians(gcj[0]));
t := atan2(gcj[0], gcj[1]) + 3e-6 * cos(3000 * radians(gcj[1]));
RETURN point(r * sin(t) + 0.0060, r * cos(t) + 0.0065);
END;
$$ LANGUAGE plpgsql IMMUTABLE STRICT PARALLEL SAFE COST 100;
================================================
FILE: pgsql/prcoords_postgis.sql
================================================
-- Depends on PostGIS and prcoords.sql
CREATE OR REPLACE FUNCTION public._latlng2geometry (p point)
RETURNS geometry AS $$
SELECT ST_SetSRID(ST_MakePoint(p[1], p[0]), 4326);
$$ LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE;
CREATE OR REPLACE FUNCTION public._geometry2latlng (p geometry)
RETURNS point AS $$
BEGIN
IF GeometryType(p) != 'POINT' THEN
RAISE EXCEPTION 'Input geom must be a point. Currently is: %', GeometryType(p);
ELSIF ST_SRID(p) != 4326 THEN
RAISE EXCEPTION 'SRID of the input geom must be 4326. Currently is: %', ST_SRID(p);
END IF;
RETURN point(ST_Y($1), ST_X($1));
END;
$$ LANGUAGE plpgsql IMMUTABLE STRICT PARALLEL SAFE;
CREATE OR REPLACE FUNCTION public.wgs_gcj (wgs geometry)
RETURNS geometry AS $$
SELECT _latlng2geometry(wgs_gcj(_geometry2latlng($1)))
$$ LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE;
CREATE OR REPLACE FUNCTION public.gcj_wgs (gcj geometry)
RETURNS geometry AS $$
SELECT _latlng2geometry(gcj_wgs(_geometry2latlng($1)))
$$ LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE;
CREATE OR REPLACE FUNCTION public.gcj_bd (gcj geometry)
RETURNS geometry AS $$
SELECT _latlng2geometry(gcj_bd(_geometry2latlng($1)))
$$ LANGUAGE SQL IMMUTABLE STRICT PARALLEL SAFE;
================================================
FILE: py/prcoords.py
================================================
'''
People's Rectified [[T:Coord|Coordinates]]
@file Utils for inserting valid WGS-84 coords from GCJ-02/BD-09 input
@author User:Artoria2e5
@url https://github.com/Artoria2e5/PRCoords
@see [[:en:GCJ-02]]
@see https://github.com/caijun/geoChina (GPLv3)
@see https://github.com/googollee/eviltransform (MIT)
@see https://on4wp7.codeplex.com/SourceControl/changeset/view/21483#353936 (Anonymous)
@see https://github.com/zxteloiv/pycoordtrans (BSD-3)
@license CC0
To the greatest extent possible, this implementation of obfuscations designed
in hope that they will screw y'all up is dedicated into the public domain
under CC0 1.0 <https://creativecommons.org/publicdomain/zero/1.0/>.
Happy geotagging/ingressing/whatever.
To make my FSF membership shine brighter, this conversion implementation is
additionally licensed under GPLv3+:
@license GPLv3+
@copyright 2016 Mingye Wang (User:Artoria2e5)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
'''
import math
import warnings
import collections
# Krasovsky 1940 ellipsoid
# @const
GCJ_A = 6378245
GCJ_EE = 0.00669342162296594323 # f = 1/298.3; e^2 = 2*f - f**2
# Epsilon to use for "exact" iterations.
# Wanna troll? Use Number.EPSILON. 1e-13 in 15 calls for gcj.
# @const
PRC_EPS = 1e-5
# Baidu's artificial deviations
# @const
BD_DLAT = 0.0060
BD_DLON = 0.0065
# Mean Earth Radius
# @const
EARTH_R = 6371000
class Coords(collections.namedtuple('Coords', 'lat lon')):
def __add__(self, other):
return Coords(self.lat + other.lat, self.lon + other.lon)
def __sub__(self, other):
return Coords(self.lat - other.lat, self.lon - other.lon)
def __abs__(self):
return math.hypot(*self)
def distance(self, other):
'''
Distance for haversine method; suitable over short distances like
conversion deviation checking
'''
hav = lambda theta: math.sin(theta / 2) ** 2
delta = self - other
return 2 * EARTH_R * math.asin(math.sqrt(
hav(math.radians(delta.lat)) +
math.cos(math.radians(self.lat)) *
math.cos(math.radians(other.lat)) *
hav(math.radians(delta.lon))
))
def sanity_in_china_p(coords):
return (0.8293 <= coords.lat <= 55.8271 and
72.004 <= coords.lon <= 137.8347)
def wgs_gcj(wgs, check_china=True):
wgs = Coords(*wgs)
if check_china and not sanity_in_china_p(wgs):
warnings.warn('Non-Chinese coords found, returning as-is: %r' % (wgs,))
return wgs
x, y = wgs.lon - 105, wgs.lat - 35
# These distortion functions accept (x = lon - 105, y = lat - 35).
# They return distortions in terms of arc lengths, in meters.
# In other words, you can pretty much figure out how much you will be off
# from WGS-84 just through evaulating them...
#
# For example, at the (mapped) center of China (105E, 35N), you get a
# default deviation of <300, -100> meters.
dLat_m = (-100 + 2 * x + 3 * y + 0.2 * y * y + 0.1 * x * y +
0.2 * math.sqrt(abs(x)) + (
2 * math.sin(x * 6 * math.pi) + 2 * math.sin(x * 2 * math.pi) +
2 * math.sin(y * math.pi) + 4 * math.sin(y / 3 * math.pi) +
16 * math.sin(y / 12 * math.pi) + 32 * math.sin(y / 30 * math.pi)
) * 20 / 3)
dLon_m = (300 + x + 2 * y + 0.1 * x * x + 0.1 * x * y +
0.1 * math.sqrt(abs(x)) + (
2 * math.sin(x * 6 * math.pi) + 2 * math.sin(x * 2 * math.pi) +
2 * math.sin(x * math.pi) + 4 * math.sin(x / 3 * math.pi) +
15 * math.sin(x / 12 * math.pi) + 30 * math.sin(x / 30 * math.pi)
) * 20 / 3)
radLat = math.radians(wgs.lat)
magic = 1 - GCJ_EE * math.pow(math.sin(radLat), 2) # just a common expr
# [[:en:Latitude#Length_of_a_degree_of_latitude]]
lat_deg_arclen = math.radians((GCJ_A * (1 - GCJ_EE)) / math.pow(magic, 1.5))
# [[:en:Longitude#Length_of_a_degree_of_longitude]]
lon_deg_arclen = math.radians(GCJ_A * math.cos(radLat) / math.sqrt(magic))
# The screwers pack their deviations into degrees and disappear.
# Note how they are mixing WGS-84 and Krasovsky 1940 ellipsoids here...
return Coords(wgs.lat + (dLat_m / lat_deg_arclen),
wgs.lon + (dLon_m / lon_deg_arclen))
def gcj_wgs(gcj, check_china=True):
'''rev_transform_rough; accuracy ~2e-6 deg (meter-level)'''
gcj = Coords(*gcj)
return gcj - (wgs_gcj(gcj, check_china) - gcj)
def gcj_bd(gcj, _dummy=False):
y, x = gcj
# trivia: pycoordtrans actually describes how these values are calculated
r = math.sqrt(x * x + y * y) + 0.00002 * math.sin(math.radians(y) * 3000)
theta = math.atan2(y, x) + 0.000003 * math.cos(math.radians(x) * 3000)
# Hard-coded default deviations again!
return Coords(r * math.sin(theta) + BD_DLAT, r * math.cos(theta) + BD_DLON)
# Yes, we can implement a "precise" one too.
def bd_gcj(bd, _dummy=False):
'''accuracy ~1e-7 deg (decimeter-level; exceeds usual data accuracy)'''
bd = Coords(*bd)
x = bd.lon - BD_DLON
y = bd.lat - BD_DLAT
# trivia: pycoordtrans actually describes how these values are calculated
r = math.sqrt(x * x + y * y) - 0.00002 * math.sin(math.radians(y) * 3000)
theta = math.atan2(y, x) - 0.000003 * math.cos(math.radians(x) * 3000)
return Coords(r * math.sin(theta), r * math.cos(theta))
def bd_wgs(bd, check_china=True):
return gcj_wgs(bd_gcj(bd), check_china)
def wgs_bd(bd, check_china=True):
return gcj_bd(wgs_gcj(bd, check_china))
def _bored(fwd, rev):
'''
generic "bored function" factory, Caijun 2014
gcj: 4 calls to wgs_gcj; ~0.1mm acc
'''
def rev_bored(bad, check_china=True):
wgs = rev(bad)
bad = Coords(*bad)
diff = Coords(99, 99) # canary
# Wait till we hit fixed point or get bored
i = 0
while i < 10 and abs(diff) > PRC_EPS:
diff = fwd(wgs, False) - bad
wgs = wgs - diff
i += 1
return wgs
return rev_bored
# Precise functions using caijun 2014 method
#
# Why "bored"? Because they usually exceed source data accuracy -- the
# original GCJ implementation contains noise from a linear-modulo PRNG,
# and Baidu seems to do similar things with their API too.
gcj_wgs_bored = _bored(wgs_gcj, gcj_wgs)
bd_gcj_bored = _bored(gcj_bd, bd_gcj)
bd_wgs_bored = _bored(wgs_bd, bd_wgs)
================================================
FILE: py/setup.py
================================================
# This file is a part of PRCoords, a public-domain library
from __future__ import with_statement
from setuptools import setup
description="Public Domain library for rectifying Chinese coordinates (gcj-02/bd-09)"
try:
with open("../README.md", "r") as f:
long_description = f.read()
except:
# Will only happen with non-wheel archives and never on pypi
long_description = description
setup(
name="prcoords",
version="1.0.2",
author="Mingye Wang",
author_email="arthur200126@gmail.com",
description=description,
long_description=long_description,
long_description_content_type="text/markdown",
url="https://github.com/Artoria2e5/PRCoords",
py_modules=["prcoords"],
classifiers=[
"Programming Language :: Python :: 2",
"Programming Language :: Python :: 3",
"Development Status :: 5 - Production/Stable",
"License :: CC0 1.0 Universal (CC0 1.0) Public Domain Dedication",
"Operating System :: OS Independent",
"Topic :: Scientific/Engineering :: GIS",
],
)
================================================
FILE: racket/prcoords.rkt
================================================
;; People's Rectified Coordinates
;; Dedicated to the Public Domain under CC0
;; No idea about the module stuff.
;; Will it handle my awful, collision-prone naming?
;;(module prcoords typed/racket
;; (provide latlon latlon-lat latlon-lon latlon? ;; Do I have to say these all?
;; I figured that before writing one for F#/Haskell/OCaml,
;; Writing one in parentheses first might be a good idea.
;; This sounds fun.
#lang typed/racket
;; I could have added some more restrictions, but whatever.
(struct latlon ([lat : Float] [lon : Float]))
;; I hear that those people in Haskell land use types to encode
;; more information. Should I do that?
;; These creepy x/y people...
(define (latlon-from-complex [c : Float-Complex]) : latlon
(latlon (imag-part c) (real-part c)))
(define (latlon-to-complex [a : latlon]) : Float-Complex
(make-rectangular (latlon-lon a) (latlon-lat a)))
;; This one is a little sloppy...
(: dcoord (-> latlon latlon
latlon))
(define (dcoord a b)
(latlon
(- (latlon-lat a) (latlon-lat b))
(- (latlon-lon a) (latlon-lon b))))
;; For looking into errors
(: dcoord-abs (-> latlon latlon
Float))
(define (dcoord-abs a b)
(max
(abs (latlon-lat (dcoord a b)))
(abs (latlon-lon (dcoord a b)))))
;; For estimating deviations
(define
(dist [a : latlon] [b : latlon]) : Float
(let
([a-lat (degrees->radians (latlon-lat a))]
[a-lon (degrees->radians (latlon-lon a))]
[b-lat (degrees->radians (latlon-lat b))]
[b-lon (degrees->radians (latlon-lon b))]
[d-lat (degrees->radians (latlon-lat (dcoord a b)))]
[d-lon (degrees->radians (latlon-lon (dcoord a b)))]
[R 6371000.]
[hav : (-> Float Float)
(λ (theta)
(* (sin (/ 2 theta)) (sin (/ 2 theta))))])
(* 2. R (cast (asin (sqrt (+ (hav d-lat)
(*
(hav d-lon)
(cos a-lat)
(cos b-lat))))) Float))))
;; What, you want a polygon check? Not now.
(: probably-bad (-> latlon
Boolean))
(define (probably-bad a)
(and
#t ;; TODO
#t
#t
#t))
;; For your sanity, no functions will be defined with the
;; rough "sanity" check on by default.
(: sanity-wrap (-> (-> latlon latlon) (-> latlon Boolean)
(-> latlon latlon)))
(define (sanity-wrap conv check)
(λ ([a : latlon])
(if (check a)
(conv a)
a)))
;; Sometimes people are like...
(: sanity-wrap-backward (-> (-> latlon latlon) (-> latlon Boolean)
(-> latlon latlon)))
(define (sanity-wrap-backward conv check)
(λ ([a : latlon])
(let ([c (conv a)])
(if (check c)
c
a))))
;; Finally a conversion. I understand that you have been
;; cursing for all these poorly-written BS.
(: wgs-gcj (-> latlon
latlon))
(define (wgs-gcj wgs)
; For (human) laziness
(let* ([gcj-ee 0.00669342162296594323] ;; Krasovsky 1940, Not What You Use With WGS-84(TM)
[gcj-a 6378245.]
[x (- (latlon-lon wgs) 105.)] ;; Deviation params
[y (- (latlon-lat wgs) 35.)]
[dlat 0.] ;; Yay, huge expressions, not today
[dlon 0.]
[rlat (degrees->radians (latlon-lat wgs))]
;; This type checker is unhappy with...
[mm (cast (- 1 (* gcj-ee (sin rlat) (sin rlat))) Positive-Flonum)]
[arclat (exact->inexact (* (/ pi 180.) gcj-a (- 1 gcj-ee) (expt mm -1.5)))]
[arclon (exact->inexact (* (/ pi 180.) gcj-a (cos rlat) (sqrt mm)))])
(latlon
(+ (latlon-lat wgs) (/ dlat arclat))
(+ (latlon-lon wgs) (/ dlon arclon))))) ;; Do you really think I am gonna finish this?
;; A rough reverse function.
(: gcj-wgs-rough (-> latlon
latlon))
(define (gcj-wgs-rough gcj)
(dcoord gcj
(dcoord (wgs-gcj gcj)
gcj)))
;; Cai's iteration.
;; Not now. Chill, it's just carrying four accumulators around and stuff.
(define
(caijun-iterate [fwd : (-> latlon latlon)]
[rough-rev : (-> latlon latlon)]
#:eps [eps : Float 1e-4]
#:maxn [maxn : Integer 10])
(λ
([bad : latlon]) : latlon
(letrec
([improve : (-> latlon latlon Integer
latlon)
(λ
(curr prev i)
;; Fixing a sloppy part in js, etc.:
;; what happens if rough-rev is just an `id`?
(if (or (and (< i maxn) (< (dcoord-abs curr prev) eps)) (= i 0))
(improve
(dcoord curr
(dcoord (fwd curr)
bad))
curr
(+ 1 i))
curr))])
(improve bad (rough-rev bad) 0))))
(define gcj-wgs : (-> latlon latlon)
(caijun-iterate wgs-gcj gcj-wgs-rough))
;; Baudu's Obfuscation.
(define
(gcj-bd [a : latlon]) : latlon
(let
([bd-delta 0.0060+0.0065i]
[c1 (latlon-to-complex a)]
[lat (latlon-lat a)]
[lon (latlon-lon a)])
(latlon-from-complex
(+
(make-polar
(+ (magnitude c1) (* 0.00002 (sin (* 3000. (degrees->radians lat)))))
(+ (angle c1) (* 0.000003 (cos (* 3000. (degrees->radians lon))))))
bd-delta))))
(define
(bd-gcj-rough [a : latlon]) : latlon
(let*
([bd-delta 0.0060+0.0065i]
[c1 (- (latlon-to-complex a) bd-delta)]
[lat (imag-part c1)]
[lon (real-part c1)])
(latlon-from-complex
(make-polar
(- (magnitude c1) (* 0.00002 (sin (* 3000. (degrees->radians lat)))))
(- (angle c1) (* 0.000003 (cos (* 3000. (degrees->radians lon)))))))))
(define bd-gcj : (-> latlon latlon)
(caijun-iterate gcj-bd bd-gcj-rough))
(define (wgs-bd [a : latlon]) : latlon
(gcj-bd (wgs-gcj a)))
(define (bd-wgs-rough [a : latlon]) : latlon
(gcj-wgs-rough (bd-gcj-rough a)))
(define bd-wgs : (-> latlon latlon)
(caijun-iterate wgs-bd bd-wgs-rough))
;; Yay!
gitextract_j7s_ktue/
├── .gitignore
├── .npmignore
├── .vscode/
│ └── settings.json
├── LICENSE.gplv3
├── README.md
├── approx/
│ └── approx.ipynb
├── cpp/
│ ├── Makefile
│ ├── badmath.hh
│ ├── bench.cc
│ ├── bench4.sh
│ ├── bench_out/
│ │ ├── README.md
│ │ ├── native_nick.md
│ │ ├── native_stdsin.md
│ │ ├── nick.md
│ │ └── stdsin.md
│ ├── demo.cc
│ ├── libprcoords.cc
│ └── prcoords.h
├── docs/
│ ├── demo.html
│ ├── index.md
│ └── proj4_plugin.js
├── haskell/
│ ├── PRCoords.cabal
│ ├── PRCoords.hs
│ └── Setup.hs
├── js/
│ ├── .npmignore
│ ├── PRCoords.d.ts
│ ├── PRCoords.js
│ ├── misc/
│ │ ├── insane_is_in_china.js
│ │ └── package.json
│ └── package.json
├── julia/
│ ├── Project.toml
│ └── src/
│ └── PRCoords.jl
├── lua/
│ └── PRCoords.lua
├── matlab/
│ ├── PRCoords.m
│ ├── bd_gcj.m
│ ├── bd_gcj_precise.m
│ ├── bd_wgs.m
│ ├── bd_wgs_precise.m
│ ├── caijun_precise.m
│ ├── gcj_bd.m
│ ├── gcj_wgs.m
│ ├── gcj_wgs_precise.m
│ ├── wgs_bd.m
│ └── wgs_gcj.m
├── package.json
├── pgsql/
│ ├── distance_agg.sql
│ ├── prcoords.sql
│ └── prcoords_postgis.sql
├── py/
│ ├── prcoords.py
│ └── setup.py
└── racket/
└── prcoords.rkt
SYMBOL INDEX (73 symbols across 13 files)
FILE: cpp/badmath.hh
type badmath (line 6) | namespace badmath {
function T (line 11) | inline T red4(T x) {
function T (line 17) | inline T sinpi_nick(T x) {
function T (line 23) | inline T sinpi_std(T x) {
function T (line 27) | inline T sinpi(T x) {
function T (line 35) | inline T cospi(T x) {
FILE: cpp/bench.cc
function uniform (line 7) | double uniform(ankerl::nanobench::Rng& rng, double a, double b){
function PRCoords (line 11) | PRCoords rand_coord(ankerl::nanobench::Rng& rng){
function main (line 15) | int main(){
FILE: cpp/demo.cc
function show_coord (line 21) | std::string show_coord(PRCoords v) {
function PRCoords (line 27) | PRCoords parse_coord(const string& s) {
function main (line 35) | int main(void) {
FILE: cpp/libprcoords.cc
function PRCOORDS_LOCAL (line 68) | PRCOORDS_LOCAL static PRCoords bored_reverse_conversion(PRCoords bad) {
function PRCoords (line 82) | PRCoords prcoords_wgs_gcj(PRCoords wgs) {
function PRCoords (line 135) | PRCoords prcoords_gcj_wgs(PRCoords gcj) {
function PRCoords (line 140) | PRCoords prcoords_gcj_bd(PRCoords gcj) {
function PRCoords (line 156) | PRCoords prcoords_bd_gcj(PRCoords bd) {
function PRCoords (line 170) | PRCoords prcoords_wgs_bd(PRCoords wgs) {
function PRCoords (line 174) | PRCoords prcoords_bd_wgs(PRCoords bd) {
function PRCoords (line 178) | PRCoords prcoords_gcj_wgs_bored(PRCoords gcj) {
function PRCoords (line 181) | PRCoords prcoords_bd_gcj_bored(PRCoords bd) {
function PRCoords (line 184) | PRCoords prcoords_bd_wgs_bored(PRCoords bd) {
function show_coord (line 193) | std::string show_coord(PRCoords v) {
function main (line 196) | int main(void) {
FILE: cpp/prcoords.h
type PRCoords (line 59) | typedef struct PRCoords {
function prcoords_in_china (line 78) | bool prcoords_in_china(const PRCoords& a) {
FILE: docs/proj4_plugin.js
constant DEG (line 5) | const DEG = Math.PI / 180
function xy_to_ll (line 7) | function xy_to_ll(p) {
function ll_to_xy (line 10) | function ll_to_xy(p) {
function xy_rename_ll (line 13) | function xy_rename_ll(p) {
function ll_rename_xy (line 16) | function ll_rename_xy(p) {
function wrap (line 20) | function wrap(f, ...args) {
FILE: js/PRCoords.d.ts
type PRCoord (line 6) | interface PRCoord {
type PRCoordOp (line 10) | type PRCoordOp = (c: PRCoord, checkChina?: boolean) => PRCoord
FILE: js/PRCoords.js
function distance (line 77) | function distance(a, b) {
function sanity_in_china_p (line 91) | function sanity_in_china_p(coords) {
function _coord_diff (line 96) | function _coord_diff(a, b) {
function _stringify (line 103) | function _stringify(c) {
function wgs_gcj (line 107) | function wgs_gcj(wgs, checkChina) {
function gcj_wgs (line 155) | function gcj_wgs(gcj, checkChina) {
function gcj_bd (line 159) | function gcj_bd(gcj, __dummy__) {
function bd_gcj (line 176) | function bd_gcj(bd, __dummy__) {
function bd_wgs (line 190) | function bd_wgs(bd, checkChina) {
function wgs_bd (line 194) | function wgs_bd(bd, checkChina) {
function __bored__ (line 200) | function __bored__(fwd, rev) {
FILE: js/misc/insane_is_in_china.js
function pnpoly (line 41) | function pnpoly(xs, ys, x, y) {
function isInGoogle (line 144) | function isInGoogle(lat, lon) {
function isInBaidu (line 151) | function isInBaidu(lat, lon) {
FILE: pgsql/distance_agg.sql
function public (line 4) | CREATE FUNCTION public._geodistance_agg_sfunc
function public (line 14) | CREATE FUNCTION public._geodistance_agg_ffunc (state _geodistance_agg_st...
FILE: pgsql/prcoords.sql
function public (line 1) | CREATE OR REPLACE FUNCTION public.geodistance
function public (line 12) | CREATE OR REPLACE FUNCTION public.geodistance (a point, b point)
function public (line 22) | CREATE OR REPLACE FUNCTION public.wgs_gcj (wgs point) RETURNS point AS
function public (line 66) | CREATE OR REPLACE FUNCTION public.gcj_wgs_bored (gcj point) RETURNS poin...
function public (line 90) | CREATE OR REPLACE FUNCTION public.gcj_bd (gcj point) RETURNS point AS
FILE: pgsql/prcoords_postgis.sql
function public (line 3) | CREATE OR REPLACE FUNCTION public._latlng2geometry (p point)
function public (line 8) | CREATE OR REPLACE FUNCTION public._geometry2latlng (p geometry)
function public (line 20) | CREATE OR REPLACE FUNCTION public.wgs_gcj (wgs geometry)
function public (line 25) | CREATE OR REPLACE FUNCTION public.gcj_wgs (gcj geometry)
function public (line 30) | CREATE OR REPLACE FUNCTION public.gcj_bd (gcj geometry)
FILE: py/prcoords.py
class Coords (line 62) | class Coords(collections.namedtuple('Coords', 'lat lon')):
method __add__ (line 63) | def __add__(self, other):
method __sub__ (line 66) | def __sub__(self, other):
method __abs__ (line 69) | def __abs__(self):
method distance (line 72) | def distance(self, other):
function sanity_in_china_p (line 87) | def sanity_in_china_p(coords):
function wgs_gcj (line 91) | def wgs_gcj(wgs, check_china=True):
function gcj_wgs (line 133) | def gcj_wgs(gcj, check_china=True):
function gcj_bd (line 138) | def gcj_bd(gcj, _dummy=False):
function bd_gcj (line 149) | def bd_gcj(bd, _dummy=False):
function bd_wgs (line 161) | def bd_wgs(bd, check_china=True):
function wgs_bd (line 164) | def wgs_bd(bd, check_china=True):
function _bored (line 167) | def _bored(fwd, rev):
Condensed preview — 51 files, each showing path, character count, and a content snippet. Download the .json file or copy for the full structured content (151K chars).
[
{
"path": ".gitignore",
"chars": 167,
"preview": "py/*/\ncpp/*.exe\ncpp/*.a\ncpp/*.dll\ncpp/*.so\ncpp/*.o\ncpp/*.obj\ncpp/*.def\ncpp/*.lib\ncpp/*.exp\nnode_modules\njulia/.vscode/se"
},
{
"path": ".npmignore",
"chars": 78,
"preview": "# npm sucks and i can only put things under git root\r\n/*\r\n!/js\r\njs/misc\r\n!/doc"
},
{
"path": ".vscode/settings.json",
"chars": 97,
"preview": "{\n \"files.associations\": {\n \"*.embeddedhtml\": \"html\",\n \"iostream\": \"cpp\"\n }\n}"
},
{
"path": "LICENSE.gplv3",
"chars": 35141,
"preview": " GNU GENERAL PUBLIC LICENSE\n Version 3, 29 June 2007\n\n Copyright (C) 2007 Free "
},
{
"path": "README.md",
"chars": 11086,
"preview": "PRCoords\n========\n\nPeople's Rectified Coordinates (PRCoords) is a cross-language implementation of \"public secret\" Chine"
},
{
"path": "approx/approx.ipynb",
"chars": 5472,
"preview": "{\n \"cells\": [\n {\n \"cell_type\": \"markdown\",\n \"metadata\": {},\n \"source\": [\n \"Approximation\\n\",\n \"============"
},
{
"path": "cpp/Makefile",
"chars": 3758,
"preview": "CXXFLAGS = -O3 -funsafe-math-optimizations -fno-math-errno -std=c++0x -Wall -Wextra -fvisibility=hidden -fvisibility-inl"
},
{
"path": "cpp/badmath.hh",
"chars": 1176,
"preview": "/**\n * Internal header for implementing \"fast\" sin(x*pi).\n */\n#include <cmath>\n\nnamespace badmath {\n // what are you "
},
{
"path": "cpp/bench.cc",
"chars": 1944,
"preview": "#include <iostream>\n#include \"badmath.hh\"\n#include \"prcoords.h\"\n#define ANKERL_NANOBENCH_IMPLEMENT\n#include \"nanobench.h"
},
{
"path": "cpp/bench4.sh",
"chars": 618,
"preview": "#!/bin/sh\n\nbench_to_file() {\n make clean\n make bench XCXXFLAGS=\"$1\"\n ./bench > bench_out/$2.md\n}\n\nnative='-marc"
},
{
"path": "cpp/bench_out/README.md",
"chars": 1527,
"preview": "# bench_out\n\nAll four files are made by nanobench; just do `./bench4.sh`.\n\n* `nick` is the version with Nick's fast sinp"
},
{
"path": "cpp/bench_out/native_nick.md",
"chars": 1412,
"preview": "Warning, results might be unstable:\n* CPU frequency scaling enabled: CPU 0 between 550.0 and 4,208.0 MHz\n\nRecommendation"
},
{
"path": "cpp/bench_out/native_stdsin.md",
"chars": 1412,
"preview": "Warning, results might be unstable:\n* CPU frequency scaling enabled: CPU 0 between 550.0 and 4,208.0 MHz\n\nRecommendation"
},
{
"path": "cpp/bench_out/nick.md",
"chars": 1412,
"preview": "Warning, results might be unstable:\n* CPU frequency scaling enabled: CPU 0 between 550.0 and 4,208.0 MHz\n\nRecommendation"
},
{
"path": "cpp/bench_out/stdsin.md",
"chars": 1502,
"preview": "Warning, results might be unstable:\n* CPU frequency scaling enabled: CPU 0 between 550.0 and 4,208.0 MHz\n\nRecommendation"
},
{
"path": "cpp/demo.cc",
"chars": 1491,
"preview": "/**\r\n * People's Rectified Coordinates, C++ demo.\r\n */\r\n\r\n#if PRCOORDS_DEMO_FORCE_STANDALONE\r\n#include \"libprcoords.cc\"\r"
},
{
"path": "cpp/libprcoords.cc",
"chars": 6243,
"preview": "/**\r\n * People's Rectified Coordinates, C++11 implementation\r\n * Should yield a C-compatible ABI.\r\n */\r\n#include \"prcoor"
},
{
"path": "cpp/prcoords.h",
"chars": 3692,
"preview": "/**\r\n * People's Rectified Coordinates, C/C++ Header.\r\n */\r\n#ifndef PRCOORDS_H\r\n#define PRCOORDS_H\r\n\r\n/** May be changed"
},
{
"path": "docs/demo.html",
"chars": 14427,
"preview": "<!DOCTYPE html>\n<html lang=\"en\">\n<head>\n <meta charset=\"utf-8\">\n<!--\nSnapshot from http://jsbin.com/zonafut/37/edit\n-->"
},
{
"path": "docs/index.md",
"chars": 247,
"preview": "<script>window.location.replace('https://github.com/Artoria2e5/PRCoords/')</script>\n<script>window.location.href = 'http"
},
{
"path": "docs/proj4_plugin.js",
"chars": 2382,
"preview": "// mirror of https://runkit.com/artoria2e5/proj4-plugin-prcoords\nconst proj4 = require(\"proj4\")\nconst prcoords = require"
},
{
"path": "haskell/PRCoords.cabal",
"chars": 2379,
"preview": "-- Initial prcoords.cabal generated by cabal init. For further \n-- documentation, see http://haskell.org/cabal/users-gu"
},
{
"path": "haskell/PRCoords.hs",
"chars": 2627,
"preview": "{-# LANGUAGE BangPatterns #-}\n{-# OPTIONS_GHC -fexcess-precision #-}\n{-# OPTIONS_GHC -optc-ffast-math -optllc--enable-un"
},
{
"path": "haskell/Setup.hs",
"chars": 46,
"preview": "import Distribution.Simple\nmain = defaultMain\n"
},
{
"path": "js/.npmignore",
"chars": 5,
"preview": "misc\n"
},
{
"path": "js/PRCoords.d.ts",
"chars": 1050,
"preview": "// Type definitions for PRCoords\r\n// Project: PRCoords\r\n\r\nexport as namespace PRCoords\r\n\r\nexport interface PRCoord {\r\n\tl"
},
{
"path": "js/PRCoords.js",
"chars": 7773,
"preview": ";(function (factory, scope) {\n\t\"use strict\"\n\tvar res = factory()\n\tif (typeof module === 'object') {\n\t\tmodule.exports = r"
},
{
"path": "js/misc/insane_is_in_china.js",
"chars": 5305,
"preview": "(function(){\n\"use strict\"\n// Insane version of the \"is in China\" check (70 points. I tried.)\n//\n// Dedicated to the Publ"
},
{
"path": "js/misc/package.json",
"chars": 612,
"preview": "{\n \"name\": \"insane-in-china\",\n \"version\": \"0.0.1\",\n \"description\": \"Routine for deciding whether one coordiate "
},
{
"path": "js/package.json",
"chars": 700,
"preview": "{\n \"name\": \"prcoords\",\n \"version\": \"1.0.3-rc1\",\n \"description\": \"Chinese coordinate obfuscation methods (GCJ-02"
},
{
"path": "julia/Project.toml",
"chars": 128,
"preview": "name = \"PRCoords\"\nuuid = \"0c59880a-3f55-4b0d-8a02-bd83932d11da\"\nauthors = [\"Mingye Wang <arthur2e5@aosc.io>\"]\nversion = "
},
{
"path": "julia/src/PRCoords.jl",
"chars": 83,
"preview": "module PRCoords\n\nstruct Coords\n lat::Float64\n lon::Float64\nend\n\nend # module\n"
},
{
"path": "lua/PRCoords.lua",
"chars": 1678,
"preview": "-- People's Rectified Coordinates\n-- https://github.com/Artoria2e5/PRCoords\n--\n-- Dedicated to the Public Domain under C"
},
{
"path": "matlab/PRCoords.m",
"chars": 258,
"preview": "function v = PRCoords()\r\n %% People's Rectified Coordinates: Chinese geographic obfuscations\r\n %% Dedicated to the Pub"
},
{
"path": "matlab/bd_gcj.m",
"chars": 366,
"preview": "function g = bd_gcj (b)\r\n % Reverse the BD-09 distortion to GCJ-02 coordinates.\r\n x = b (2) - 0.0065;\r\n y = b (1) - 0"
},
{
"path": "matlab/bd_gcj_precise.m",
"chars": 282,
"preview": "function g = bd_gcj_precise (b, tol, maxn)\r\n % Reverse the BD-09 distortion to GCJ-02 coordinates in a precise way.\r\n "
},
{
"path": "matlab/bd_wgs.m",
"chars": 132,
"preview": "function w = bd_wgs (b)\r\n % Reverse the BD-09 distortion to WGS-84 coordinates.\r\n g = bd_gcj (b);\r\n w = gcj_wgs (g);\r"
},
{
"path": "matlab/bd_wgs_precise.m",
"chars": 284,
"preview": "function w = bd_wgs_precise (b, tol, maxn)\r\n % Reverse the BD-09 distortion to WGS-84 coordinates in a precise way.\r\n "
},
{
"path": "matlab/caijun_precise.m",
"chars": 902,
"preview": "function fun = caijun_precise (fwd, rev, o, tol, maxn)\r\n % usage: fun = caijun_precise (@fwd, @rev)\r\n %\r\n % With a pr"
},
{
"path": "matlab/gcj_bd.m",
"chars": 360,
"preview": "function b = gcj_bd (g)\r\n % Apply the BD-09 distortion to GCJ-02 coordinates.\r\n x = g (2);\r\n y = g (1);\r\n\r\n r = sqrt"
},
{
"path": "matlab/gcj_wgs.m",
"chars": 130,
"preview": "function w = gcj_wgs (g)\r\n % Reverse the GCJ-02 distortion in a rough way.\r\n gg = wgs_gcj (g);\r\n w = g * 2 - gg;\r\nend"
},
{
"path": "matlab/gcj_wgs_precise.m",
"chars": 213,
"preview": "function w = gcj_wgs_precise (g, tol, maxn)\r\n if nargin < 2\r\n tol = 1e-13;\r\n end\r\n if nargin < 3\r\n maxn = 10;\r\n"
},
{
"path": "matlab/wgs_bd.m",
"chars": 130,
"preview": "function b = wgs_bd (w)\r\n % Apply the BD-09 distortion to WGS-84 coordinates.\r\n g = wgs_gcj (w);\r\n b = gcj_bd (g);\r\ne"
},
{
"path": "matlab/wgs_gcj.m",
"chars": 1361,
"preview": "function r = wgs_gcj (w)\r\n % Apply the GCJ-02 distortion to WGS-84 coordinates.\r\n wlat = w (1); wlon = w (2);\r\n\r\n % K"
},
{
"path": "package.json",
"chars": 611,
"preview": "{\n \"name\": \"prcoords\",\n \"version\": \"1.0.5\",\n \"description\": \"Chinese coordinate obfuscation methods (GCJ-02, BD"
},
{
"path": "pgsql/distance_agg.sql",
"chars": 767,
"preview": "CREATE TYPE _geodistance_agg_state AS\n(distance double precision, lat double precision, lon double precision);\n\nCREATE F"
},
{
"path": "pgsql/prcoords.sql",
"chars": 3227,
"preview": "CREATE OR REPLACE FUNCTION public.geodistance\n(alat double precision, alng double precision, blat double precision, blng"
},
{
"path": "pgsql/prcoords_postgis.sql",
"chars": 1208,
"preview": "-- Depends on PostGIS and prcoords.sql\n\nCREATE OR REPLACE FUNCTION public._latlng2geometry (p point)\nRETURNS geometry AS"
},
{
"path": "py/prcoords.py",
"chars": 6955,
"preview": "'''\nPeople's Rectified [[T:Coord|Coordinates]]\n@file Utils for inserting valid WGS-84 coords from GCJ-02/BD-09 input\n@au"
},
{
"path": "py/setup.py",
"chars": 1100,
"preview": "# This file is a part of PRCoords, a public-domain library\r\nfrom __future__ import with_statement\r\nfrom setuptools impor"
},
{
"path": "racket/prcoords.rkt",
"chars": 6140,
"preview": ";; People's Rectified Coordinates\n;; Dedicated to the Public Domain under CC0\n\n;; No idea about the module stuff.\n;; Wil"
}
]
About this extraction
This page contains the full source code of the Artoria2e5/PRCoords GitHub repository, extracted and formatted as plain text for AI agents and large language models (LLMs). The extraction includes 51 files (138.8 KB), approximately 43.1k tokens, and a symbol index with 73 extracted functions, classes, methods, constants, and types. Use this with OpenClaw, Claude, ChatGPT, Cursor, Windsurf, or any other AI tool that accepts text input. You can copy the full output to your clipboard or download it as a .txt file.
Extracted by GitExtract — free GitHub repo to text converter for AI. Built by Nikandr Surkov.