Input
Results
| Operation | Result | ΔObfs/m | ΔRoundtrip/m |
|---|---|---|---|
| WGS → GCJ | (14.13182804, -89.26335693) 14°7′54.5809″ N, 89°15′48.0849″ W | 3.954729731753357e+3 | 6.158858885419617e+0 |
| WGS → BD | (14.13765254, -89.25686455) 14°8′15.5491″ N, 89°15′24.7124″ W | 4.675979366825549e+3 | 6.152072280502806e+0 |
| GCJ → WGS | (14.13483196, -89.33664307) 14°8′5.3951″ N, 89°20′11.9151″ W | 3.9547036742554947e+3 | 1.0176794678929253e+1 |
| BD → WGS | (14.12889017, -89.34314461) 14°7′44.0046″ N, 89°20′35.3206″ W | 4.678409630023731e+3 | 1.0239270560262563e+1 |
| GCJ →cai WGS | (14.13489983, -89.33657995) 14°8′5.6394″ N, 89°20′11.6878″ W | 3.948228803160858e+3 | 2.728819796431917e-5 |
| BD →cai WGS | (14.12895905, -89.34308063) 14°7′44.2526″ N, 89°20′35.0903″ W | 4.670744871903358e+3 | 1.026647204709377e-4 |
| GCJ → BD | (14.13919297, -89.29350175) 14°8′21.0947″ N, 89°17′36.6063″ W | 9.570710889706104e+2 | 3.534822758329935e-3 |
| BD → GCJ | (14.12738192, -89.30651184) 14°7′38.5749″ N, 89°18′23.4426″ W | 9.646214115634926e+2 | 1.83802851035915e-2 |
| BD →cai GCJ | (14.12738176, -89.30651187) 14°7′38.5743″ N, 89°18′23.4427″ W | 9.646363816418456e+2 | 5.167119506501094e-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.