Version 20 (modified by mdavis, 13 years ago) ( diff )


Welcome to Proj4J

Proj4J is a Java library to transform point coordinates from one geographic coordinate system to another, including datum transformations.

The core of this library is a port of the PROJ.4 C library. The basic algorithms, concepts and coordinate system definitions supplied by PROJ.4 are exposed via a Java class model which follows standard Java conventions and OO best practices.

Proj4J is a part of the MetaCRS group of projects, hosted by OSGeo.


Status: Currently this library is still being created, and is not yet ready for download


  • The PROJ.4 documentation is the best reference for details of the coordinate system specification language, projection algorithms and supported parameters.
  • the Version History lists the evolution of features of the library

Mailing List

A mailing list is available for users and developers of Proj4J as well as for discussion of general cartographic projections related issues. Subscription, unsubscription and a web archive can be found at


Related Resources

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