Creating a DEM from vector data

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This article is part of the old QGIS tutorial, which is no longer maintained. The article will soon be edited to provide a standalone exercise.

  1. Add the vector layer goesrtm.shp. This is a point vector generated from SRTM digital elevation model with a 90m interval.
  2. Zoom in and click with the “Identify Features” tool on a point and identify the attributes.
  3. Open the GRASS toolbox with LOCATION: goegk, MAPSET: user1
  4. Import the vector layer goesrtm.shp with the of the GRASS tools module list.
  5. We now want to interpolate the points to a surface with the same raster resolution like the multispectral LANDSAT7 ETM+ Bands: 30 m. Open the GRASS shell Grass shell.png. Type in g.region. rast=etm10 Enter
  6. Control the region settings with Edit current GRASS region of the GRASS tools.
  7. Create a new surface with the Inverse Distance Weighted (IDW) Interpolation algorithm using from the modules list: filename: goesrtm, attribute field: Z, Number of interpolation points: 24, Name of the raster file: goedem.
  8. Open the GRASS module r.out.gdal:
    Input layer: goedem
    GIS format: GTiff
    Format: Byte
    Save output as goedem in your /geodata folder
    Click Run
  9. Set the properties for the new layer goedem:
    • Render as Single gray band
    • For color map choose Pseudocolor from the dropdown-list.
    • Mark Invert color map
    • Change settings for standard deviation

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