Tutorial: Process groundwater data in QGIS

4. Define the study area

4.4. Create a country boundary by dissolving features

In this subsection we're going to clip the Shire buffer 10km layer to the boundary of Malawi.

We could download a country boundary from for example the Natural Earth dataset. Here, however, we can use the Geology UTM or Hydrogeology UTM layer which cover only Malawi. The advantage of this method is that the boundaries will better match the layers.

We can create the country boundary by dissolving all features in the Geology layer (similar for the Hydrogeology layer, but here we'll explain it for the Geology layer).

1. In the main menu go to Vector | Geoprocessing Tools | Dissolve...

2. In the Dissolve dialogue choose Malawi_GIS_data Geology UTM as Input layer and save the Dissolved layer to the Malawi_GIS_data.gpkg with the name Malawi country boundary. Keep the other settings as default so we dissolve all fields in the layer.

Dissolve to Malawi country boundary

3. Click Run. Click Close after processing.

Now the Malawi country boundary layer appears in the map canvas.

Malawi country boundary

The next step is to clip the Shire buffer 10km layer to the Malawi country boundary.