spatialreference.org is a website redesigned in 2023 by Javier Jimenez Shaw, based on PROJ.org and now managed by the PROJ development team. It helps assists others in their understanding, discovery, and usage of spatial reference systems (SRS). This refreshed version is a continuation of prior work of Howard Butler, Christopher Schmidt, Dane Springmeyer and Josh Livni started in 2007.

The source code of this website is available at https://github.com/OSGeo/spatialreference.org.


There are currently several catalogs of SRS on this website: EPSG, ESRI, IAU:2015, IGNF, NKG and OGC. Its content is automatically refreshed from the PROJ' SRS database, at each PROJ release.

Each SRS is available in different formats under the root URL https://spatialreference.org/ref/authority/code:

Note that the previous version of this website allowed user-defined SRS to be submitted. This functionality has been removed, and the website now only presents objects that have been vetted by reference authorities. To get the old data, look for the file "sr-org.json" in the git repository.

Spatialreference has a sibling project under the PROJ umbrella: CRS Explorer. It has a different approach displaying all the available CRSs and filtering them. To show them all just click on https://crs-explorer.proj.org/?all=true