QGIS: Becoming a GIS Power User

Extracting vectors

Clipping is great, except when you don't want to alter the original geometries, such as when you want to select overlapping features. Or, in other cases, you just want filter the geometries based on nonspatial attributes. To achieve both of these results, you can utilize the Selection tools in combination with Save Layer As.. to extract just the features of interest. This recipe uses spatial selection methods to extract a subset of original polygons without altering them.

Getting ready

We'll use the same data as the previous recipe, geology.shp and census_wake2000.shp.

How to do it…

1. Select polygons from geology.shp that overlap with Wake County (census_wake2000.shp) by navigating to Vector | Research Tools | Select by location