# Proj4js Home Page

# Welcome to Proj4js

This is a JavaScript library that provides methods for coordinate transformations between map projections and longitude/latitude, including datum transformations, in a web client.

To use the Proj4js, you first create a source and destination Proj4js.Proj objects, passing in a projection code (e.g. EPSG:4326). You can then use the Proj4js.transform() method, passing in map XY as a point object and the source and destination projection objects, and it returns the point coordinate in the destination projection.

source |  | dest
--- | --- | ---
CRS: |  |  | CRS: |
| Projection - datum |  |  | Projection - datum
x,y |  | units |  | x,y |  | units

For more information on Proj4js and to report bugs, please visit the Proj4js Trac and Wiki at OSGeo.