[GRASS-user] The unit of `glob_rad` in `r.sun` with a CRS in feet

[Kodi Arfer]

I don't know much about GRASS, but I've been calling out to it from R with `rgrass` to use `r.sun`. In particular, I use `r.sun` mode 2 to turn a digital-surface-model raster I built from Rhode Island lidar data into an irradiance raster. I notice that the manual says that the unit of `glob_rad` in this case is Wh m^(-2) day^(-1). However, my input raster's CRS is EPSG:6568, which is in feet. Does that mean the `glob_rad` unit is actually Wh ft^(-2) day^(-1)? I'm on GRASS 7.8.2, which also produces a warning when ingesting the input raster ("WARNING: Datum <Unknown_based_on_GRS80_ellipsoid> not recognised by GRASS and no parameters found").