LatLong Converter

GCJ-02 to WGS84 Converter

GCJ-02
WGS84
GCJ-02
WGS84

About GCJ-02 Coordinate System

1Definition

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.

2Development History

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.

3Applications

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.

Encrypted Offset

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.

China Region Only

The encryption offset only applies within mainland China. Coordinates outside China pass through without modification.

Industry Standard

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.

About WGS84 Coordinate System

1Definition

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.

2Development History

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.

3Applications

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.

GPS Compatibility

WGS84 is the native coordinate system of the Global Positioning System (GPS), ensuring direct compatibility with all GPS receivers and satellite navigation systems worldwide.

Global Standard

As the most widely adopted geodetic datum, WGS84 provides a consistent global reference frame for mapping, surveying, and geospatial data exchange across international boundaries.

High Precision

With continuous refinements, WGS84 achieves centimeter-level accuracy globally, making it suitable for high-precision applications like surveying, drone navigation, and scientific research.

GCJ-02 to WGS84 Conversion Guide

📐 Conversion Formula
// GCJ-02 → WGS84 (iterative method)
// Since the GCJ-02 offset is non-linear, iterative approach is used:
function gcj02ToWgs84(lat, lon) {
    dLat = transformLat(lon - 105.0, lat - 35.0)
    dLon = transformLon(lon - 105.0, lat - 35.0)
    radLat = lat × π / 180
    magic = 1 - 0.00669342162296594323 × sin²(radLat)
    sqrtMagic = √magic
    dLat = (dLat × 180) / ((6335552.717 / (magic × sqrtMagic)) × π)
    dLon = (dLon × 180) / ((6378245.0 / sqrtMagic × cos(radLat)) × π)
    wgsLat = lat × 2 - (lat + dLat)
    wgsLon = lon × 2 - (lon + dLon)
}

Converting GCJ-02 back to WGS84 uses the mathematical inverse of the forward transformation. Since the offset algorithm is non-linear, the inverse uses a double-iteration approach: first compute the forward offset, then subtract it from the original coordinates (offset × 2 - forward = inverse).

📋 Operation Steps
  1. Enter GCJ-02 coordinates in decimal degrees format
  2. The system applies the inverse offset algorithm
  3. Results are WGS84 coordinates suitable for GPS and international applications
  4. Verify converted coordinates on Google Maps or other WGS84-based services
💡 Tips
  • GCJ-02 to WGS84 conversion is essential for using Chinese map data internationally
  • Accuracy is typically within 1 meter for most locations
  • Coordinates outside China pass through unchanged

Frequently Asked Questions

The accuracy depends on the specific coordinate systems being converted. For standard geographic transformations between GCJ-02 and WGS84, typical accuracy is within sub-meter range under normal conditions. For systems requiring 7-parameter transformations, accuracy depends heavily on the quality and regional relevance of the parameters used. Always verify results for critical applications.

Yes! Our tool supports batch conversion. Simply enter multiple coordinate pairs, one per line, in the input field on this page. All coordinates will be processed simultaneously, and you can download the results as an XLSX file for further analysis or integration.

Enter coordinates in the format: latitude, longitude (one pair per line). Latitude should be the first value, longitude the second. For example: 23.05105,113.37149. Ensure latitude is between -90 and 90, and longitude is between -180 and 180.

For this conversion, standard parameters may be sufficient for most applications.

Absolutely. All coordinate conversions are performed entirely in your browser using client-side JavaScript. Your data is never sent to any server, ensuring complete privacy and security of your geographic information. This is especially important for sensitive location data.

GCJ-02 gcj-02 (mars coordinate system) is a geodetic datum used in china for geospatial data. it applies an... WGS84 wgs84 (world geodetic system 1984) is the global standard geodetic reference system used by gps. it . The conversion between them accounts for differences in their ellipsoid parameters, datum origins, and any encryption offsets.