proj.4

proj.4 is a standard UNIX filter function which converts geographic longitude and latitude coordinates into cartesian coordinates (and vice versa), and it is a C API for software developers to include coordinate transformation in their own software. proj.4 is maintained on GitHub.

Platform	Test Status and Coverage
Travis
AppVeyor
Coverage

Full documentation is available as a single PDF at https://raw.githubusercontent.com/OSGeo/proj.4/gh-pages/proj4.pdf

Documentation

• Download
• FAQ
• Applications
• Projections
• Parameters
• Geodesic calculations
• Grids
• HTPD
• Development
• Glossary
• License
• References

Mailing List

The Proj.4 mailing list can be found at http://lists.maptools.org/mailman/listinfo/proj

Indices and tables

• Index
• Search Page