How to Perform Slope Analysis from DEM in QGIS

Quick summary

Slope analysis in QGIS converts a Digital Elevation Model (DEM) raster into a slope map showing terrain gradient values. Using the built-in Processing Toolbox, you can run the Slope tool on any .tif DEM file and instantly visualize slope data as a new raster layer.

Steps

1. On the top menu, click Layer, then select Add Layer, and choose Add Raster Layer.
2. Click Browse (…) to select a file from your computer and load it into the project.
3. Select a .tif file, then click Open.
4. Click Add to confirm and add the file to the project.
5. The .tif file layer will open and be added to the Layers Panel and map canvas.
6. Go to the Processing Toolbox on the right-side menu.
7. In the search bar, search for and select Slope.
8. A dialog box will open. In the Elevation Layer dropdown menu, select your DEM raster.
9. Optionally, leave the Z factor value as 1 if your DEM uses the same horizontal and vertical units, and adjust it if the units differ.
10. Then, click Run to execute the slope analysis.
11. Click Close to exit the dialog box. A new slope raster layer will be added to the Layers Panel showing computed slope values.