3.4. Spatial Data: DSM Generator¶
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
|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.
- Starts the calculations.
- Closes the plugin.
- One GeoTIFF is created, a DSM.