Comparing Datasets with Overlays

Introduction

Manipulating multiple spatial datasets, especially when involving numerous polygon or line datasets, often requires creating new geometries based on the areas where these datasets intersect or remain separate. This kind of manipulation is available through overlay operations.

In general, overlay operations in GIS are key methods that allow for the modification and reclassification of geometries based on their spatial interactions with other shapes. These operations create new output geometries and are essential when trying to understand the overlap or difference between spatial datasets, such as land use categories and flood zones.

The overlay operations available in GeoPandas are:

• Intersection

• Union

• Difference

• Symmetric difference

The effect of these operations can be visualized in the figure below.