../../_images/logo_proj.png ../../_images/OSGeo_project.png


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.


Website: https://proj.org/

Licence: X/MIT Open Source license

Software Version: 9.1.1

Supported Platforms: Windows, Linux, Mac

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

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