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:
- As WKT1 / Well-known Text v1 / OGC 01-009:
- As WKT2:2019 / Well-known Text v2 / OGC 18-010r7:
- /esriwkt.txt: WKT variant used by Esri software, typically for Shapefile .prj side-car file, as text content. Example
- /projjson.json: as JSON content, following the PROJ JSON encoding, which is equivalent to WKT2:2019. Example
- /proj4.txt: as PROJ.4 CRS string. Note this encoding is considered as legacy, and is generally lossy, particularly regarding geodetic or vertical datums. Example
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
- Un site pour les Systèmes de Références Spatials -- Link back to SpatialReference.org