When running the QGIS application, the user has a range of tools available to create and manipulate geospatial features. For example, the Add Feature tool lets the user create a new feature, while the Move Feature tool and the Node tool allow the user to move and edit existing geospatial features. However, these tools are only available within QGIS itself—if you want to write an external application on top of the PyQGIS library, these built-in tools aren't available, and you will have to implement these features yourself.

In this chapter, we will look at what is involved in adding functionality to a PyQGIS application so that the user can select and edit geospatial features. In particular, we will examine: