BD-09 to GCJ-02 Converter
About BD-09 Coordinate System
BD-09 (Baidu Coordinate System) is a geodetic system developed by Baidu, based on GCJ-02 with additional encryption for use in Baidu Maps and related services.
Baidu developed BD-09 by applying a secondary encryption layer on top of GCJ-02 to further obfuscate coordinates. It is proprietary to Baidu and used exclusively in their mapping ecosystem.
BD-09 is used exclusively in Baidu Maps, Baidu Navigation, and Baidu LBS API. It is the most encrypted coordinate system among Chinese map services.
BD-09 adds a second encryption layer on top of GCJ-02, making it the most heavily obfuscated coordinate system used in China.
Used exclusively within Baidu's mapping platform. If you're developing with Baidu Maps API, all coordinates must be in BD-09 format.
Conversion between BD-09 and other systems relies on reverse-engineered algorithms that provide sub-meter accuracy.
About GCJ-02 Coordinate System
GCJ-02 (Mars Coordinate System) is a geodetic datum used in China for geospatial data. It applies an encrypted offset to WGS84 coordinates to comply with national regulations.
Developed by the Chinese National Bureau of Surveying and Mapping, GCJ-02 was introduced to implement the national security policy on geospatial information. Most Chinese map services use this system.
GCJ-02 is used by all Chinese government-approved map services including AMap (Gaode), Tencent Maps, and Apple Maps in China. It is required for any mapping application operating within mainland China.
GCJ-02 applies a non-linear offset algorithm to WGS84 coordinates, shifting positions by up to several hundred meters. The exact algorithm is classified by the Chinese government.
The encryption offset only applies within mainland China. Coordinates outside China pass through without modification.
GCJ-02 is the mandatory coordinate system for all commercial map services operating in China. Converting between WGS84 and GCJ-02 is essential for international data integration.
BD-09 → GCJ-02 Conversion Guide
// BD-09 → GCJ-02 (via WGS84 intermediate)
// Most non-WGS84 conversions use a two-step process:
// Step 1: BD-09 → WGS84 (using reverse transformation)
// Step 2: WGS84 → GCJ-02 (using forward transformation)
// This ensures maximum accuracy by routing through
// the well-defined global WGS84 reference system
// rather than attempting a direct transformation{{from}} to {{to}} is performed via a two-step transformation through WGS84 as an intermediate reference system, ensuring maximum accuracy.
- Enter your BD-09 coordinates in the input field (latitude, longitude, one pair per line)
- Click the Convert button to transform coordinates from BD-09 to GCJ-02
- Review the converted GCJ-02 coordinates in the output field
- Copy the results or save them as an XLSX file for further use
- Ensure coordinates are within valid ranges before conversion
- For batch conversions, enter one coordinate pair per line
- Verify a sample of converted coordinates on your target platform
- All conversions are performed client-side for complete data privacy