So far, the user can choose which map layers are displayed, and can zoom and pan the map view. The only thing missing is the entire point of the application: exploring landmarks. To do this, we'll have to implement our application's explore mode.

In the previous chapter, we saw how we can use a QgsMapToolIdentify subclass to respond when the user clicks on a vector feature. We're going to use the same logic here to implement a new map tool, which we'll call ExploreTool. Add the following class definition to your lex.py module after the PanTool class definition:

class ExploreTool(QgsMapToolIdentify):
    def __init__(self, window):
        QgsMapToolIdentify.__init__(self, window.mapCanvas)
        self.window = window

    def canvasReleaseEvent(self, event):
        found_features = self.identify(event.x(), event.y(),
                                       self.TopDownStopAtFirst,
                                       self.VectorLayer)
        if len(found_features...