I noticed that QGIS changes the CRS of newly generated layers, that is, I have a layer in my desired CRS, then I use a toolbox function with that layer as input, and the resulting layer is often in a different CRS. In my concrete example, I downloaded National Map elevation data and added it as a first layer, so the project CRS was EPSG:4269. I then reprojected that layer to EPSG:3719. I open a new QGIS project and add the reprojected layer, because I want EPSG:3719 as my project CRS. Then I use r.fill.dir on the EPSG:3719 layer and the resulting layer CRS is EPSG:2956. Then I use r.watershed with the depressionless DEM and the resulting flow direction and accumulation layers are in EPSG:2956. I have the setting checked that new layers should get the CRS of the project, but apparently it's not doing that.

Please note that this is not the case when I use SAGA functions, i.e., the SAGA fill algorithm comes up with the correct CRS (EPSG:3719).

Am I missing something obvious? I could of course warp/reproject all new layers, but that is not the point...

  • How exciting, it's converting between US and Canadian GCS. Is the data in Canada or the US? A wild guess--internally r is using a kinda generic UTM 12N definition. When it's done, it tries to retrieve the input GCS/UTM combo but ends up picking the first one that it finds instead. – mkennedy Aug 22 at 16:59
  • Yes, QGIS is taking internationality to a new level! :-) The data are from the US. I just checked, the resulting CRSs are independent of the CRS that goes into the functions. Looks like I might really have to reproject each and every newly generated layer... – Rincewind Aug 23 at 17:24

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