Calculating a slope
Slope is one of the most basic parameters that can be derived from a DEM. It corresponds to the first derivative of the DEM, and it represents the rate of change of the elevation. It is computed by analyzing the elevation of each cell and comparing this with the elevation of the surrounding ones. This recipe shows you how to compute slope in QGIS.
Getting ready
Open the DEM that we prepared in the previous recipe.
How to do it…
In the Processing Toolbox option, find the Slope algorithm and double-click on it to open it:
Select the DEM in the Input layer field.
Click on Run to run the algorithm.
The slope layer will be added to the QGIS project.
How it works…
Slope is calculated from a DEM elevation model by analyzing the cells around a given one. This analysis is performed by the slope algorithm from the GDAL library.
There's more…
There are several ways of using the slope algorithms in QGIS. Here are some comments and ideas about this.
Using a ratio for elevation values
If the units...
