PostGIS in Action

Chapter 4. Geometry functions

 

This chapter covers

• Core geometry properties
• Geometry functions that take one geometry argument

 

In the previous chapters we defined the various kinds of geometries that PostGIS provides, how to create them, and how to add them to the database. In this chapter and the next we’ll introduce the core set of functions that work with geometries. This chapter will concentrate on functions that tend to work with single geometries. In the next, we’ll work with functions that relate two or more geometries.

PostGIS offers well over 300 functions and operands. To get an overview, we’ve developed a taxonomy that’s driven by intent of use. This is by no means a rigorous classification nor one that will neatly sort each ...