I have a SRTM DEM and need to find whether it has voids or gaps in the data.

  • No absolutely not. Just stuck with finding gaps in DEM of a basin.. I couldn't find any gaps when I see manually.. I wanted to make sure is there any other way to find Voids or Gaps. – Kishore Apr 24 at 10:54
  • What do you mean by a gap or void? Do you mean an area with a "missing data" code? For example, you might have a DEM where -9999 means "No Data". – Spacedman Apr 24 at 12:28
  • yes how to determine "missing data" in DEM? – Kishore Apr 24 at 12:57
  • yes missing data? is there any way to find out using raster calculator ? – Kishore Apr 24 at 13:11

The DEM will have a nodata value that means there is a void (no information there). Load the .hgt file into QGIS / Arc, look at the layer properties, to find out what it is. Visually, you could:

  • Make the layer completely black.
  • Set the nodata value to be transparent (should be automatic).
  • Look for voids.

Programmatically, you could

  • load the raster to an array and
  • count nodata values.

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