Using a map tool to draw points on the canvas
QGIS contains a built-in functionality to zoom and pan the map in custom applications. It also contains the basic hooks to build your own interactive tools. In this recipe, we'll create an interactive point tool that lets you mark locations on the map by clicking on a point.
Getting ready
We will use the application framework from the previous Adding standard map tools to the canvas recipe, so complete that recipe. We will extend that application with a new tool. The complete version of this application is available in the code samples provided with this book.
How to do it...
We will set up the button, signal trigger, and actions as we do with all map tools. However, because we are building a new tool, we must also define a class to define exactly what the tool does. To do this, we need to perform the following screenshot:
- First, we define our point tool's button in the actions portion of our application. Place this line after the
QAction...
