Chapter 2. Geometry types

 

This chapter covers

  • PostGIS geometry_columns metatable
  • Geometry types: points, linestrings, polygons
  • Geometry collection types: multipoints, multilinestrings, multipolygons
  • Curved geometry types and 3D geometry types

In the first chapter we gave you a brief taste of what PostGIS is and which basic geometries it supports. This chapter continues by explaining how PostGIS manages geometry data stored in the database. You’ll learn about those tables in all PostGIS-enabled databases that provide an inventory of the geometry table columns and of the available spatial reference systems. We then show you the definition and characteristics of points, linestrings, and polygons and how to work with them in a PostGIS-enabled database. After covering these single geometries, we move on to geometries that are made up of collections of single geometries: multipoints, multi-linestrings, multipolygons, and geometrycollections. We then demonstrate creating the less-commonly used curved geometries and 3D geometries and outline the issues to consider when using these less-common geometry types.

2.1. Geometry columns in PostGIS

2.2. A panoply of geometries

2.3. Summary

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