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I am trying to merge several (70 at least) raster files (a digital elevation model, ASTER DEM v2). I am using QGIS and I use the tool "Raster > Miscellaneous > Merge".

I works well and I get the new raster, but the elevation values are not concordant with the values on the original rasters. For instance, there are individual rasters with elevation >2000m, and in the new raster I get values until 1500m.

I have also used "Raster > Miscellaneous > Build Virtual Raster", but the same happens. I have tried as well to merge fewer raster files; it still does not work.

What should I do? Any suggestions?

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  • been having the exact same problem
    – Rodrigues
    Jul 2, 2017 at 23:32

1 Answer 1

Reset to default
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Go to properties of the ASTER DEM layer and go to Style and do the following:

enter image description here

  1. Use Min/Max
  2. In the Extent, use Actual (Slower) => Load. Then check if the pixel values were updated or not.
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  • After that, the range values are still the same... In the layer with the merged raster files and in the individual rasters...
    – mto23
    Sep 2, 2016 at 8:13
  • Have you tried both "Full extent" and "Current extent"?
    – ahmadhanb
    Sep 2, 2016 at 8:31
  • I am trying now. This takes a while, maybe the last time I tried I didn't give it enough time. I will let you know if this works!
    – mto23
    Sep 2, 2016 at 9:45
  • The values change with the options "full extent" and "Actual (slower)". But it seems to take a very long time, I wasn't able to let the "load" finish yet... Do you know of any other option? Maybe using GRASS...?
    – mto23
    Sep 2, 2016 at 13:00

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