[GRASS-dev] PROJ6 support in GRASS

Martin Landa landa.martin at gmail.com
Thu Nov 7 09:46:50 PST 2019


čt 7. 11. 2019 v 15:17 odesílatel Markus Metz
<markus.metz.giswork at gmail.com> napsal:
> PROJ 6 support is not yet finished in GRASS. Currently it sort of works in master and relbr78, but I expect troubles because GRASS is heavily relying on deprecated proj strings as CRS definitions. This is becoming problematic e.g. when creating locations from GDAL/OGR datasets because GRASS goes from OGR spatialreference through proj string to GRASS definition.

OSGeo4W packages are planned to be switched to GDAL3/PROJ6 soon, are
you aware of any known bugs?

> For GDAL 3 + PROJ 6, GRASS should switch to WKT as main CRS definition format, ideally also storing a WKT definition next to PROJ_INFO. When creating locations from GDAL/OGR datasets, GRASS should go from OGR spatialreference through WKT to GRASS definition, and probably use the new PROJ6+ methods as much as possible.

Yes, good topic for

> When getting the projection info of a GRASS location, GRASS should then check in that order 1) WKT, 2) EPSG or other SRID, 3) GRASS native definition (which deviated from proj definition some decades ago).
> That means, g.proj, r.in.gdal, r.external, v.in.ogr, v.external need updates, and the mechanism of conversion between different formats of CRS definitions in lib/proj needs to be largely rewritten.

This task for next stable GRASS release (7.10?) I guess.


Martin Landa

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