I have a DEM as a Geotiff and I have conducted slope analysis in QGIS. I've done this many times and everything was ok but this time I received reversed values: 0 for max slope and 89 for min slope. I have no idea what is wrong. Geotiff was generated from .asc files and seems to be ok.

I suppose there is something wrong with the first Geotiff file. I took "native" .asc file and made slope analysis without a problem. After that I generated Geotiff from the Slope.asc and is also fine.

  • Which tool did you use to calculate slope?
    – HDunn
    Dec 31, 2015 at 8:10

1 Answer 1


Can you not try to inverse the max and min slope vlaues in QGIS, providing that is what software you are using. I use .asc files all the time, but not seen this issue.

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