1. Classification of coordinate systems
WGS84 coordinate system : Earth coordinate system, international common coordinate system.
GCJ02 coordinate system : Mars coordinate system, encrypted coordinate system of WGS84 coordinate system; used by Google domestic maps, AutoNavi, and QQ maps.
BD09 coordinate system : Baidu coordinate system, the encrypted coordinate system of GCJ02 coordinate system.
2. What is the coordinate system obtained by the android native system?
Why is this question listed separately? Originally, my idea was that the android system belongs to Google. Logically speaking, the coordinate system should be the Mars coordinate system. Picking the coordinates, the result obtained does not match the current actual position, which can be hundreds of meters or more away. Then I converted the latitude and longitude of the natively acquired coordinates into Mars coordinates through coordinate conversion, and the display on the Gaode map is basically the same as the current position. Before converting to Mars coordinates, I rotated according to the earth coordinate system, and it was displayed normally on Gaode and Baidu maps.
So it is concluded that the coordinates obtained by the android native system are the earth coordinate system.
3. How to check the latitude and longitude on the map
Map coordinate system conversion This is to convert the WGS84 coordinate system, GCJ02 coordinate system, and BD09 coordinate system at will. The usage is as shown in the figure.
4. Through the link below, you can directly query the above converted latitude and longitude on the map
Baidu Map Pickup Coordinate System
AutoNavi Map Pickup Coordinate System
There is also one that can choose Baidu, AutoNavi, and Tencent Maps
5. Coordinate correction ( tested, more accurate )
Since the GPS data uses the WGS84 coordinate system, the Baidu map uses the BD-09 coordinate system, and the AutoNavi map uses the Mars coordinate system (CGJ-02).
Therefore, after converting the degree format to the degree format, the application platform also needs to convert the data from the WGS84 coordinate system to the corresponding coordinate system, otherwise the positioning will be biased.
The positioning result is based on the GPS positioning correction map .
———————————————
Reprinted in: https://blog.csdn.net/qq_36771588/article/details/109855375
Reference link: https://www.jianshu.com/p/24702227eb5e