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PROJ

PROJ is a library that provides methods to transform between different coordinate reference systems. A geographic coordinate reference system allows all points on the earth to be described as a set of coordinates (such as latitude, longitude and elevation). Different systems are used to represent the tridimensional earth on a flat, bidimensional map.

PROJ is used in MapServer, GRASS GIS, PostGIS, Mapnik, Thuban, OGDI, TopoCad, OGRCoordinateTransformation and various others.

PROJ has been translated from C to other languages. These sub-projects include:

  • Proj4js (JavaScript) - used in OpenLayers.
  • CS-Map (C++) - used in MapGuide.
  • GeoTIFF/libgeotiff (C++).
  • Proj4J (Java).
  • EPSG.io - website to retrieve coordinate system definitions
  • SpatialReference.org - website to retrieve coordinate system definitions (obsolete).
proj screenshot

Core Features

  • Provides point transformation from one coordinate reference system to another.
  • Includes transformation between datums.
  • Large number of projection classes supported.

Implemented Standards

PROJ uses coordinate system definitions defined by the European Petroleum Survey Group (EPSG). Well Known Text (WKT) format.

Details

Website: https://proj.org/

Licence: X/MIT Open Source license

Software Version: 7.2.1

Supported Platforms: Windows, Linux, Mac

API Interfaces: C, C++, Python, Java, Ruby

Support: https://lists.osgeo.org/mailman/listinfo/proj