Input
Results
| Operation | Result | ΔObfs/m | ΔRoundtrip/m |
|---|---|---|---|
| WGS → GCJ | (19.23112641, -69.56747813) 19°13′52.0551″ N, 69°34′2.9213″ W | 3.4232279866151016e+3 | 3.4386087327695907e+0 |
| WGS → BD | (19.23715921, -69.56098978) 19°14′13.7732″ N, 69°33′39.5632″ W | 4.1176533179037e+3 | 3.450393613645791e+0 |
| GCJ → WGS | (19.23553359, -69.63252187) 19°14′7.9209″ N, 69°37′57.0787″ W | 3.4231822886388222e+3 | 3.4885572484629845e+0 |
| BD → WGS | (19.22972528, -69.63894736) 19°13′47.011″ N, 69°38′20.2105″ W | 4.108670455670029e+3 | 4.657856777511026e+0 |
| GCJ →cai WGS | (19.23555818, -69.63250130) 19°14′8.0094″ N, 69°37′57.0047″ W | 3.4212249415935303e+3 | 4.745578956980659e-6 |
| BD →cai WGS | (19.22975762, -69.63891908) 19°13′47.1274″ N, 69°38′20.1087″ W | 4.105366419989226e+3 | 1.0422398618680044e-6 |
| GCJ → BD | (19.23912645, -69.59357668) 19°14′20.8552″ N, 69°35′36.876″ W | 9.328403125974061e+2 | 3.7916415028837517e-3 |
| BD → GCJ | (19.22752157, -69.60642654) 19°13′39.0777″ N, 69°36′23.1355″ W | 9.340231048656008e+2 | 3.069205016370626e-2 |
| BD →cai GCJ | (19.22752183, -69.60642644) 19°13′39.0786″ N, 69°36′23.1352″ W | 9.339955947947385e+2 | 4.1383040243909205e-5 |
Permalink to this result. Toggle sections: Notes, FAQ, footer. And print.
Notes
- 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
LCPRNG.
If you are doing Wikipedia or any kind of archival work, use it to avoid introducing extra error.
- BD is defined in terms of GCJ, hence the last three functions.
- This demo omits the “in China” sanity check. Data regarding
Baidu’s behavior with overseas maps is needed for further
decisions. Observations:
- Unlike Google Maps, Baidu's map in Hong Kong is fully subject to BD-09 ∘ GCJ-02 chained distortions.
- Coordinates in Russia, outside of the sanity check rectangle, uses WGS-84 or and/or friends.
- TODO: check along the boundary.
FAQ
- What is this all about?
- The PRC government requires all local map services to use an obfuscated, deviation-orienated coordinate system. Click on the “restriction” link to read the full Wikipedia article.
- Why should I care?
- With half a kilometer of deviation, GCJ-02 and friends fucks up your Ingress games, causes crazy errors in elevation profiles along cycle routes, and cheerfully leads you into roadside ditches plus a bone fracture.
- Why doesn’t Google/Bing correct its Chinese data served to global users?
- I don’t know. Perhaps they are afraid of getting fined or further kicked out of China. Maybe try OpenStreetMap next time?
- Why are you writing another implementation?
- Because I got bored.
- How does Caijun’s iterative method work?
- Cai has explained the method in full in his R implementation. Go read it, or read Wikipedia.