With the AREA_MI <= 1000 selection, let's add a field and populate it with a marker based on this selection.
Click on the Field Calculator button in the attributes toolbar to open up the field calculator.
This window contains considerable information; there is a great deal of power within the field calculator. In our case, we want to create a new field called small_area and assign yes if it is =< 1000, or no if it is >1000. As with many of the tools in GIS, there are several ways of doing this. The method we will use is designed to help you to build confidence first. In chapter 6, Extending QGIS with Python, we will look at more complex queries and show how this particular query could be addressed in one step.
As shown ...
