Preparing elevation data
In this recipe, we will show you how to perform terrain analysis in QGIS. Terrain analysis algorithms assume certain characteristics in the DEMs that are used as inputs, so it is important to know them and prepare these DEMs if they are needed. This recipe shows you how to do this.
Getting ready
Open the dem_to_prepare.tif layer. This layer contains a DEM in the EPSG:4326 CRS and elevation data in feet. These characteristics are unsuitable to run most terrain analysis algorithms, so we will modify this layer to get a suitable one.
How to do it…
Reproject the layer to the EPSG:3857 CRS, using the Save as... entry in the context menu that appears by right-clicking on the layer name.
Open the resulting reprojected layer.
Open the Processing raster calculator and select the reprojected layer as the only raster input in the Input layers field. Enter
a * 0.3048in the Formula field. Run the algorithm.
How it works…
Most of the algorithms that we are going to use assume that the...
