In this chapter, we finished implementing the ForestTrails mapping application. Our application now lets the user add, edit, and delete tracks; view and enter track attributes; set the start and end points; and display the shortest available path between those two points. As we implemented the application, we discovered an issue with tracks not connecting, and solved that problem by adding support for vertex snapping. We also learned how to write a custom QDialog to let the user view and edit attributes, and how to use the QGIS Network Analysis library to calculate the shortest available path between two points.

While the ForestTrails application is only one example of a specialized mapping application, it provides a good example of how to implement standalone mapping applications using PyQGIS. You should be able to use much of the code for your own mapping applications, as well as build on the techniques covered in previous chapters when you write your own mapping applications using...