Input
Results
| Operation | Result | ΔObfs/m | ΔRoundtrip/m |
|---|---|---|---|
| WGS → GCJ | (45.74335185, 24.39665039) 45°44′36.0667″ N, 24°23′47.9414″ E | 5.596281311913901e+2 | 4.476690976350918e-1 |
| WGS → BD | (45.74934346, 24.40320606) 45°44′57.6365″ N, 24°24′11.5418″ E | 1.2256075011319867e+3 | 4.1190275267765497e-1 |
| GCJ → WGS | (45.74442815, 24.38230961) 45°44′39.9413″ N, 24°22′56.3146″ E | 5.596227982815238e+2 | 5.807293145400187e-1 |
| BD → WGS | (45.73838993, 24.37585084) 45°44′18.2037″ N, 24°22′33.063″ E | 1.2217544424627608e+3 | 7.954125774675654e-1 |
| GCJ →cai WGS | (45.74443335, 24.38230884) 45°44′39.9601″ N, 24°22′56.3118″ E | 5.597445058214718e+2 | 2.779105771146401e-4 |
| BD →cai WGS | (45.73839702, 24.37585220) 45°44′18.2293″ N, 24°22′33.0679″ E | 1.2212689115501248e+3 | 9.619360736624926e-4 |
| GCJ → BD | (45.74990874, 24.39598520) 45°44′59.6715″ N, 24°23′45.5467″ E | 8.382688464599606e+2 | 3.511112076670794e-3 |
| BD → GCJ | (45.73784950, 24.38302173) 45°44′16.2582″ N, 24°22′58.8782″ E | 8.380517791171242e+2 | 2.8212274471576194e-2 |
| BD →cai GCJ | (45.73784967, 24.38302146) 45°44′16.2588″ N, 24°22′58.8773″ E | 8.380489427843031e+2 | 1.7921225469447188e-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.