7.6.3. Intersect

Identically to ArcMap, the intersect operation in QGIS computes a geometric overlap of two layers. This can be best demonstrated by the use of two polygon layers with different geometries:

  1. Go to Vector.
  2. Select Geoprocessing Tools.
  3. Choose Intersect.
  4. Choose the newly created buffer layer as Input vector layer.
  5. Leave the checkbox beneath Use only selected features blank.
  6. Select the layer commune_boundary_FR.shp (where the city of Fribourg should still be selected).
  7. Check Use only the selected feature of this layer of the city of Fribourg (Fig. 97).
  8. Click OK.

The new layer contains only the common area of the two polygons (the geometry of the buffer within the city of Fribourg).

Fig. 97. Using the Intersect Tool, overlapping areas are written to the resulting layer (the attributes of both original layers will be preserved).