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I have a task to figure out how many agricultural areas are located in a defined altitude. The agricultural areas were a polygon, while the altitude/DMNV was a raster. I converted it to a polygon and tried to clip it together, but it says that the data base for the altitude is not supported or does not exist. What am I to do?

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    more details helps. which process is the error: the convert raster to polygon, or the clip? which software are you using? how many bands are in the raster file?
    – sutan
    Jun 14 at 10:31
  • Are you using ArcGIS Pro or ArcMap?
    – PolyGeo
    Jun 14 at 11:12

1 Answer 1

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I guess with DMNV you mean a Digital Elevation Model (DEM) as a raster layer. To prepare, make sure all your layers are in the same CRS (projection).

  1. Use Menu raster > raster calculator to create a binary (pixel values only 0 or 1) raster for the condition of altitude. Something like raster@1 > 500 and raster@1 < 1000 (where raster is the name of your DEM layer and 1 is the number of the band containing altitude values) for altitutdes between 500 and 1000 meters.

  2. Then convert the polygons with your agricultural areas to a raster: Menu Raster > Convert > Rasterize with A fixed value to burn set to 1. Be sure again to use the same CRS and resolution as the DEM layer.

  3. Then again use raster calculator to determine where both conditions (elevation between 500 and 1000 and agricultural area) are met, thus where both rasters have pixel values of 1. Use the expression elevation@1 * agricultural@2 = 1 where elevation and agricultural are the names of the input raster layers. You'll get an output raster where pixel values = 1 represents the areas where both conditions are fulfilled.

You might want to vectorize the result using Menu Raster > Conversion > Polygonize.

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