I'm currently working on fixing some errors in some old DTMs.

The issue is there are pixels with a value of "-1.4013e-45" which are all over the rasters. I'm looking for a way to remove these, as they're in areas where there should be NoData.

I have tried to generate a Mask, for valid pixels within the DTM, but the "-1.4013e-45" also get passed through, as they are within the range of valid pixels.

1 Answer 1


A couple of options:

1 - r.mapcalc

r.mapcalc "output_with_nodata = if(input_dem<=0.01, null(), input_dem)"

2 - Save as + "no data" range

right-click on the layer name, Export -> Save as

then make sure you tick the No data values box, and enter a sensible range. In your case it coul be for example (-1; 0.01)

enter image description here

3 - r.mapcalc.simple

A, well, simpler / GUI style r.mapcalc

enter image description here

  • 1
    Thanks for this, it's something I can work with! I still don't understand why DTM's are output to greater than 4 decimal places, it makes no sense. Thanks again!! Commented Nov 5, 2022 at 17:09

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