Geometry relationships

We want to filter the geocaching points that fall inside a given boundary (a country, state, city, and so on.). In order to perform this kind of filtering, we need to verify every point and see whether it's inside the polygon representing the boundary.

In geoprocessing, the relations between the two geometries are described by a set of known predicates. These relationships are very important because they allow conditions to be made, so one can perform operations and calculations.

Shapely comes with a complete set of predicates that analyze the relation of the two geometries. Before we go further in our app, let's take a look at the possible relation checks.

Touches

This is true if the geometries have one or more points in common without their interiors intersecting.

Crosses

This is true if there is an intersection between the two objects without one containing the other.

Contains

This indicates if one object completely contains the other object; all the boundaries, lines,...