Computing road slope using elevation data
A common geospatial workflow is to assign raster values to a coincident vector layer so that you can style or perform further analysis on the vector layer. This recipe will use this concept to illustrate the steepness of a road using color by mapping values to the road vector from a slope raster.
Getting ready
You will need to download a zipped directory from https://github.com/GeospatialPython/Learn/raw/master/road.zip and place the directory, named road, in your qgis_data directory.
You must also have a verison of QGIS which includes GRASS and SAGA. For more information, see the Installing QGIS for development recipe from Chapter 1, Automating QGIS,
How to do it...
We'll start with a DEM and compute its slope. ...
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