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 and GCTCP C 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 group of projects and uses the same MIT style license as PROJ.4.

This package contains the proj4 module for Node.js.

Node.js is an event-based server-side JavaScript engine.