A project involving spatial data is typically geographically limited to within a specified boundary area, the so-called project area. The input data can come from multiple sources and usually extends outside the project area. Removing this excess data is sometimes critical to speed up spatial processes, and at the same time, it reduces data volume. Reductions in data volumes can also result in secondary speed-ups, for example, less time to transfer or copy the data.

In this recipe, we will take a boundary polygon represented by a circle Shapefile, and then remove all excess LineStrings that are outside this circle.

This process of clipping will remove all lines outside the clip area—that is, our project area of interest.