I'm using QGIS with a flat-world approximation dataset and for my specific use, geometric coordinates on a 1 unit = 1 metre scale are perfect.

Unfortunately, QGIS doesn't have EPSG:404000 built-in, and complains if I try to create a custom CRS with +proj="" as the instructions on http://spatialreference.org/ref/sr-org/7589/ say.

Is there any way to teach QGIS about EPSG:404000 and get it to work basically without projection ?

  • Do you have a particular reason for not working with just any projected coordinate system that uses metres (for instance the standard equidistant cylindrical, EPSG:3786)? As long as you're not reprojecting or trying to reference with other datasets it doesn't matter which projection you're using (and I'm assuming you don't need to do either of those things). – Jake Feb 7 '13 at 13:02
  • I would prefer 3785. The bounding box for y coordinates goes up to +/-19971868, while 3786 is limited to +/-10007554: I don't know what happens if your data falls outside the bounds. – AndreJ Feb 7 '13 at 15:31
  • @AndreJoost: I believe those bounds only define the area that can be projected back to a geographic coordinate system, which doesn't matter in this case. QGIS lets you work outside the bounds without trouble. – Jake Feb 7 '13 at 16:03
  • That's actually a good suggestion that might provide a workaround. I still wonder if it is possible to tell QuantuamGIS "please treat this as a 2D plane, thank you very much". – Tom Feb 7 '13 at 16:59
  • 1
    @Tom: But why do you need that? All projected coordinate systems are just 2D planes, the only difference between them being that they have different equations attached to them for mapping the 2D plane onto a sphere, with 404000 being a special case because it doesn't have that equation. As long as you don't use that equation (by reprojecting your data), there is no difference between normal projected coordinate systems and a "true" 2D plane. – Jake Feb 7 '13 at 17:17

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