China Map Coordinate Transform
Convert between WGS-84, GCJ-02, and BD-09 coordinate systems used in China mapping platforms.
About China Coordinate System Transform
Convert between WGS-84, GCJ-02, and BD-09 coordinate systems used in China mapping platforms. Essential for developers working with Chinese map services.
Coordinate Systems Explained
WGS-84 is the GPS standard used globally. GCJ-02 (Mars coordinates) is used by Gaode (Amap) and Tencent Maps. BD-09 is used by Baidu Maps. Each system offsets coordinates differently.
How to Use
Enter latitude and longitude values, select the source and target coordinate systems, then click Convert. The result will show the coordinates in the target system with 8 decimal places.
▶Why do I need coordinate transformation?
Chinese map services use different coordinate systems. GPS returns WGS-84, but Gaode/Amap uses GCJ-02 and Baidu uses BD-09. You must convert between them for accurate map positioning.
▶Is the conversion accurate?
The conversion uses standard algorithms with sub-meter precision. However, the GCJ-02 algorithm is an approximation of the official (undisclosed) transformation.
▶Can I convert in reverse?
Yes. You can convert from any system to any other system. Select the source and target systems using the dropdown menus.