How to Calculate the Slope of a DEM in 3 Steps:

  1. Open the DEM in QGIS
  2. Fill Sinks
  3. Run The Slope Tool

Step 1

Open the DEM in QGIS

Note: In this example, we use a DEM exported from the Equator Data Menu.

Open your DEM shapefile in QGIS by dragging and dropping the file into the map space.


Image of our DEM in QGIS

Step 2

Fill Sinks

Note: DEMs from Equator automatically fill sinks when exported.

If you did not get your DEM from Equator, follow the instructions below:

Use Fill sinks (wang & liu) tool.

Processing Toolbox → SAGA → Terrain Analysis – Hydrology Fill sinks (wang & liu)

Match the settings in the screenshot below and click Run.

Fill Sinks in QGIS

Using the fill sinks tool to generated a Filled DEM layer

Step 3

Run The Slope Tool

Now that we have projected our DEM onto our project, we will run the Slope tool:

Processing Toolbox → Taster Terrain analysis Slope

Set the input layer as your DEM, and adjust the other input settings as you deem appropriate (in this case we elected to leave the default settings):

Calculate Slopes in QGIS

Using the Slope tool to generate the final layer


You now have a layer with the slope of your DEM calculated in degrees!

We hope this helped, and feel free to take a look at some of Equator’s other blogs and “How-to tutorials”!

SlopeMap in QGIS