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I am trying to take a Digital Elevation Model raster layer and “burn” polygons into it, so that they show up in the DEM layer. I know there are methods for burning streams/rivers into raster DEMs, but these would be lines, and I am not sure about polygons.

I have the following DEM layer with Reservoir polygons overlaid : enter image description here

I want to take my reservoir polygons and “burn” them into the DEM layer so that they become a part of the raster layer. Can this easily be done in QGIS?

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    Do you have depth value of the reservoir, or do you have desired end elevation for the reservoir area?
    – Cushen
    Dec 20, 2022 at 4:14
  • I have area of inundation of reservoirs and reservoir volume.
    – arda
    Dec 20, 2022 at 4:21
  • then I can get depth bolue of the reservoir. so what should I do next?
    – arda
    Dec 20, 2022 at 4:36
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    What is currently in the area where the polygon is. Is it flat? i.e. lake surface elevation?
    – Cushen
    Dec 20, 2022 at 5:03
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    The rasterize tool in the processing toolbox can rasterize also polygons. I suppose it is using internally gdal_rasterize gdal.org/programs/gdal_rasterize.html. Just select your burn value to match with the desired color in your palette.
    – user30184
    Dec 20, 2022 at 7:30

1 Answer 1

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Rasterize will do this.

Add the elevation value that you want to burn in to the DTM to your polygons attribute table. Run rasterize on your polygon using the value you just added into the attribute table. Select your actual DTM as the output, not a new file. You'll get the polygon 'burned' into the original DTM.

(please save a copy of your DTM first).

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