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I used the Raster>Analysis>"Proximity (Raster distance)" tool in QGIS in order to create a raster of distances to a particular value in another raster. This is the same sort of thing someone might do for a proximity to mainland analysis... only I'm using it for proximity to something else (a bathymetric slope of more than 10 degrees).

Proximity tool in QGIS

When I run the Proximity tool with my slope raster as the input file, and "Dist unit" as GEO, I receive a warning that "Pixels not square, distances will be inaccurate." I think this makes sense, as I'm using EPSG:4326.

Pixels not square warning

Unfortunately for me, the distances are important, and they are far off reasonable values in my region of interest (though their relative magnitudes make sense, which is useful). If I use PIXEL as the "Dist unit" instead, I do not receive this warning, and the distance values for the generated raster make sense. But how do I generate a raster from this with values that represent geometric distances (in meters)?

Resulting raster

  • Have you considered reprojecting your raster to a projected coordinate system? – user2856 Oct 22 '18 at 8:01
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As @Luke suggests in his comment, one solution is to use the raster reprojection tool (Raster>Projections>Warp) to reproject the input raster prior to proximity analysis. In my instance, I reprojected the raster indicating the location of the feature of interest from EPSG:4326 to 3857. Then I ran the new raster through the proximity tool, using GEO as the "Dist units". Band values in the output raster are now in meters.

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