Proj4js is a JavaScript library to transform point coordinates from one coordinate system to another, including datum transformations.
This library is a port of both the [PROJ.4](http://trac.osgeo.org/proj/) and [GCTCP C](http://edcftp.cr.usgs.gov/pub//software/gctpc) libraries to JavaScript. Enabling these transformations in the browser allows geographic data stored in different projections to be combined in browser-based web mapping applications.
Proj4js is a part of the [MetaCRS](http://wiki.osgeo.org/wiki/MetaCRS) group of projects and uses the same MIT style license as PROJ.4.
