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I am trying to convert a DEM file from meters to feet using a fairly simple formula. The range of elevations in the source file is 551 - 1250.

  • When I multiply by 3.28 I get nan results.
  • When I multiply by 1.1 I get the expected results (although obviously, this is not a useful conversion to feet from meters)

I didn't have this problem with the essen version of qgis, but I recently upgraded to 2.18.

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  • Testing several combinations of Pixel Types and projections (incl. on-the-fly; latlon and projected) I could not replicate your case. I had to put human error in, i.e. run Raster Calculator on an unexpected area. (As you know it happens.. when we forgot to push Current layer extent.) It cannot be the cause, as human error causes error regardless values (3.28 / 1.1), or QGIS version. I found similar cases in GIS SE, but turned out every case was unique. It also struck me none of provided answers could reproduce those errors. You might have to find other ways until the root cause is found. – Kazuhito Nov 26 '16 at 11:20
  • By the way, in my QGIS 2.18 (GNU/Linux Debian), I don't have this problem. Are you using Windows? – xunilk Nov 26 '16 at 11:26
  • @xunilk Hi, I used QGIS 2.18 on Windows 10; neither had this error. Is this Mac specific? – Kazuhito Nov 26 '16 at 12:06
  • @Kazuhito Sorry, but I don't know. – xunilk Nov 27 '16 at 9:11
  • @xunilk Thanks, and I am sorry. Just deduced without clear reason. – Kazuhito Nov 27 '16 at 10:25

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