About GeoCoordConv

GeoCoordConv is a free, open-source coordinate conversion toolbox designed for GIS developers, surveyors, and data analysts who work with Chinese coordinate systems.

Supported Coordinate Systems

WGS84

World Geodetic System 1984 — the GPS standard used globally.

GCJ02

Chinese national standard (Mars coordinates) with nonlinear offset from WGS84.

BD09

Baidu coordinate system with additional offset from GCJ02.

BD09MC

Baidu Mercator projection — planar coordinates in meters.

Features

  • • All 10 conversion directions between WGS84, GCJ02, BD09, and BD09MC
  • • Batch CSV processing for bulk coordinate conversion
  • • AOI (Area of Interest) string to GeoJSON polygon parser
  • • REST API for programmatic access
  • • Sub-meter conversion accuracy
  • • Open source and free to use