Input
Results
| Operation | Result | ΔObfs/m | ΔRoundtrip/m |
|---|---|---|---|
| WGS → GCJ | (44.32836356, 23.78339188) 44°19′42.1088″ N, 23°47′0.2108″ E | 6.123740187805021e+2 | 1.9026002482030686e+0 |
| WGS → BD | (44.33439784, 23.78985219) 44°20′3.8322″ N, 23°47′23.4679″ E | 1.2744374283087668e+3 | 1.9167457486003412e+0 |
| GCJ → WGS | (44.32957644, 23.76808812) 44°19′46.4752″ N, 23°46′5.1172″ E | 6.12367764037024e+2 | 1.6142242104571018e+0 |
| BD → WGS | (44.32349131, 23.76168301) 44°19′24.5687″ N, 23°45′42.0588″ E | 1.2733592944453655e+3 | 1.3928039575595375e+0 |
| GCJ →cai WGS | (44.32957080, 23.76806937) 44°19′46.4549″ N, 23°46′5.0497″ E | 6.137811877265112e+2 | 8.36010775732941e-6 |
| BD →cai WGS | (44.32348753, 23.76166632) 44°19′24.5551″ N, 23°45′41.9988″ E | 1.2747262013515776e+3 | 3.1539979683668818e-6 |
| GCJ → BD | (44.33502807, 23.78215484) 44°20′6.1011″ N, 23°46′55.7574″ E | 8.450446127264951e+2 | 4.2033666295591895e-2 |
| BD → GCJ | (44.32289316, 23.76935035) 44°19′22.4154″ N, 23°46′9.6613″ E | 8.45535212610216e+2 | 3.465170710715447e-2 |
| BD →cai GCJ | (44.32289331, 23.76934997) 44°19′22.4159″ N, 23°46′9.6599″ E | 8.455403587808004e+2 | 1.2229547183799364e-4 |
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.