How do I do that in PostGIS

For those who are unsure if SQL is a sufficient language for performing GIS tasks, this book is for you. This guide follows the topic headings from the book How do I do that in ArcGIS/Manifold, as a way to illustrate the capabilities of PostGIS SQL engine for accomplishing classic GIS tasks. With this book as a resource, users will be able to perform many classic GIS functions using nothing but SQL.