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

In this example, we use a DEM shapefile exported from the Equator Site BuilderOpen your DEM shapefile in QGIS by simply dragging and dropping it into the map space:

Image of our DEM in QGIS

Step 2

Fill Sinks

Next, we will fill in the sinks, using Fill sinks (wang & liu) tool:

Processing Toolbox → SAGA → Fill sinks (wang & liu)

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 → 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):

Using the Slope tool to generate the final layer


By now you should 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”!