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the transformation from gcj02 to wgs84 is not precise

Open KingWang93 opened this issue 5 years ago • 2 comments

the precise in wuhan as bellow(11 meters): image

it's possible to solve it?

or, do you know any better method to calculate more precise?

KingWang93 avatar Dec 30 '18 14:12 KingWang93

No. I can’t ensure the precision across all places. I tested it when I was in Shanghai.

On Sun, Dec 30, 2018 at 10:10 PM KingWang93 [email protected] wrote:

the precise in wuhan as bellow(11 meters): [image: image] https://user-images.githubusercontent.com/17794023/50547966-8861c700-0c7f-11e9-912a-7f499b6c6e16.png

it's possible to solve it?

or, do you know any better method to calculate more precise?

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googollee avatar Dec 30 '18 14:12 googollee

Neither OSM or your path data are that precise. OSM people trace data from their GPS devices and from satellite maps. These sky-based images do not always align perfectly with the coordinates they are referencing, especially when on uneven terrain found in chongqing when it becomes impossible as they are often not captured from the zenith (90° overhead).

You are dealing with street map data, not precision drone strikes. Being off by 500 meters is definitely wrong, but being off by 10 meters is probably not worth complaining about since streets can be that wide too. Feel free to improve OSM if you feel that you are absolutely right. Remember to map the center lines of streets and make sure your GPS is reporting a HDOP better than the current OSM result.


and no, the problem with eviltransform's gcj in #44 does not account for the difference. taking an example point in chongqing as a representative:

w	(29.55833333, 106.56666667)
g_prc	(29.55544346, 106.57036277)
g_evt	(29.55545751, 106.57036283)

the distance between the two results is only 1.56 meters. Even with the non-precise reverse mode, the round-trip error is only 0.74 meters.

Artoria2e5 avatar Jun 28 '19 03:06 Artoria2e5