WGS84 to BD-09 Converter
About WGS84 Coordinate System
WGS84 (World Geodetic System 1984) is the global standard geodetic reference system used by GPS. It defines an Earth-centered, Earth-fixed coordinate system and geodetic datum.
Developed by the U.S. Department of Defense in 1984, WGS84 has undergone several refinements (WGS84(G730), WGS84(G873), WGS84(G1150), WGS84(G1762)) to improve accuracy through GPS satellite observations.
WGS84 is the default coordinate system for GPS receivers worldwide. It is used in aviation, maritime navigation, Google Maps, OpenStreetMap, GIS applications, and scientific research.
WGS84 is the native coordinate system of the Global Positioning System (GPS), ensuring direct compatibility with all GPS receivers and satellite navigation systems worldwide.
As the most widely adopted geodetic datum, WGS84 provides a consistent global reference frame for mapping, surveying, and geospatial data exchange across international boundaries.
With continuous refinements, WGS84 achieves centimeter-level accuracy globally, making it suitable for high-precision applications like surveying, drone navigation, and scientific research.
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.
WGS84 → BD-09 Conversion Guide
// WGS84 → BD-09 (two-step transformation)
// Step 1: WGS84 → GCJ-02
[gcjLat, gcjLon] = wgs84ToGcj02(lat, lon)
// Step 2: GCJ-02 → BD-09
x = gcjLon
y = gcjLat
z = √(x² + y²) + 0.00002 × sin(y × 3000 × π / 180)
θ = atan2(y, x) + 0.000003 × cos(x × 3000 × π / 180)
bdLat = z × sin(θ) + 0.006
bdLon = z × cos(θ) + 0.0065BD-09 applies an additional encryption layer on top of GCJ-02. The transformation uses polar coordinates with trigonometric functions to create the secondary offset. First convert WGS84 to GCJ-02, then apply the BD-09 specific polar transformation.
- Enter WGS84 coordinates in latitude,longitude format
- The tool first converts WGS84 → GCJ-02 internally
- Then applies the BD-09 secondary encryption to produce the final coordinates
- The output coordinates can be used directly with Baidu Maps API
- BD-09 is only used by Baidu Maps - other Chinese map services use GCJ-02
- The double encryption makes BD-09 the most obfuscated coordinate system
- Always verify converted coordinates by plotting them on the target map service