Note

Need help? Please let us know in the UMEP Community.

3.4. Spatial Data: DSM Generator

  • Developer:

Name

Institution

Nils Wallenberg

Gothenburg
  • Introduction:

    Digital Surface Models (DSMs) is not always available for the area you want to investigate. The DSM Generator can be used to create or alter a DSM by using information from a polygon building footprint layer where a building height attribute is available. An option to acquire building footprints, and also in some cases building height from Open Street Map data, is available from this plugin.

  • Dialog box
    ../_images/DSMGenerator.png

    Fig. 3.5 Dialog for the DSM generator plugin

  • Dialog sections:

top

input DEM data is specified

middle upper

input polygon with height data or OSM is specified

middle

map extent is specified

middle lower

to specify the output DSM and output resolution

bottom

to run the calculations
  • Digital Elevation Model:

    A raster file containing elevation values needed to create the DSM. Raster elevation data (DEM) can be retrieved from e.g. OpenDEM.

  • Polygon Vector File:

    A polygon vector file including height values of buildings needed to create the DSM.

  • Necessary attributes:

    Building height values in meters.

  • Use Open Street Map:

    Tick this in if you do not have a polygon layer with building heights. Open Street Map (© OpenStreetMap contributors) data will be used instead. If no building height is found building level height will be used instead. Set to appropriate value, e.g. a three level building with building level height set to 3 will be 3 * 3 = 9 meters high.

  • Save OSM as shapefile:

    Tick this in if you want to save the Open Street Map data as a polygon layer. This can be used if you want to look at what values has been used and if you want to add values manually.

  • Map extent:

    Set either to map canvas extent or extent from layer. Extent have to be smaller or equal to the raster DEM extent specified in the top section.

  • Digital Surface Model:

    Set output for the generated DSM. Also set output resolution.

  • Run:

    Starts the calculations.

  • Close:

    Closes the plugin.

  • Output:

    One GeoTIFF is created, a DSM.

  • Remarks:

    • The DEM raster and map canvas should be in a projection with meters as units.

    • Raster elevation data (DEM) can be retrieved from e.g. OpenDEM.

    • If you use Open Street Map make sure you read Open Street Map © OpenStreetMap contributors.