In this talk we will demonstrate spatial data analysis on the relational database system PostgreSQL (http://www.postgresql.org) equipped with the spatial extension PostGIS (http://www.postgis.org). We will gradually introduce some of the optimisation techniques provided by PostgreSQL, by applying them to the solution of increasingly complex problems belonging to the PostGIS domain. Our aim is to point out as clearly as possible the main ideas behind each example, showing the link in both projects between development of new features and the need to tackle real-world problems. Topics mentioned in this talk include: the special index types GiST and SP-GiST; custom database objects, such as data types, functions and operators; query and workload profiling.