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 projection algorithms, concepts and coordinate system definitions are all taken directly from PROJ.4. These are wrapped in 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.
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The PROJ.4 documentation is the best reference for details of the coordinate system specification language, projection algorithms and supported parameters.
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the [Version History](doc/Proj4J Version History.html) lists the evolution of features of the library
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the Javadoc describes the API
A mailing list is available for users and developers of Proj4J.
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Subscription, unsubscription and a web archive are at http://lists.osgeo.org/mailman/listinfo/proj4j.
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Direct link to the mailing list archive.
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SVN repository: http://svn.osgeo.org/metacrs/proj4j.
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Browse source here.
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Submit a new bug report (you need to login with an OSGeo Userid)
Proj4J is licensed under the Apache License, Version 2.0.
- The PROJ.4 site has a comprehensive list of resources dealing with Coordinate Systems in general and the PROJ.4 library in particular.
The Proj4J codebase is based on a partial port of PROJ.4 carried out by JHLabs circa 2006. The JHLabs port provided a large number of the PROJ.4 projections, but did not support some PROJ.4 features such as datum transformation.