PostGIS in Action

One Minute Bottom Line

Review

Who should read this book?
It starts off with a categorization of potential readers: GIS practitioners and programmers, database practitioners and scientists and researchers working with geospatial data. Working as an enterprise stuff developer and having fiddled only a little with geospatial data, I do not really fit into one of these categories. Nevertheless “PostGIS In Action” served me well as a quick start guide to GIS and helped me getting up to speed developing geospatial applications on (not only) PostGIS.

What's in it?
The book is organized in three parts. The first one, “Learning PostGIS”, explains the basics of working with spatial data. Geometry types, functions, relationships and spatial reference systems are covered in this part. It sets a solid foundation of the nuts and bolts required to solve spatial problems. Every chapter in this part is packed with examples to work through. As early as page 16, the authors actually advise you to install PostGIS. From there on, you will rarely find more than two consecutive pages without example code you can – and should – reproduce.

The second part, “Putting PostGIS to work”, shows how to apply this knowledge in a larger context. Instead of working through complete example use cases, „PostGIS in Action“ presents techniques to solve spatial problems. Examples include distance measuring in combination with different spatial reference systems, creating lines from points and creating grids or break up larger areas into equally sized regions which is useful for analysis. For each technique, the rationale for using it is presented and explained by easily digestible examples.

This part also contains a chapter on performance tuning which introduces you to the query planner and how to optimize the query plan as well as optimizing the geometries your queries operate on.

The third part is concerned with integration with popular tools from the geospatial tool chain and open source extensions. It contains a plethora of tips not only on how to integrate tools with PostGIS but also PostGIS agnostic introductions to these tools. Take for example the chapter about using PostGIS in web applications: It explains the scope of mapping servers, compares different mapping server implementations like MapServer and GeoServer, gives installation instructions for them. It also gives an introduction to the OpenLayers JavaScript library for rendering maps on web pages. Obviously, it is also shown how data from PostGIS can be retrieved using these tools.

This broad scope is exemplary for “PostGIS in Action”: It is not primarily focused on covering PostGIS in depth but mainly on how to practically apply it in typical scenarios.

In “Using PostGIS in a desktop environment”, open source GIS desktop tools like QGIS, OpenJUMP and uDig are introduced and compared to each other. For each tool, the steps necessary to connect to from PostGIS are described in detail.

What I liked about this book
I really like the hands-on approach typical for the In Action series. The authors obviously are extremely proficient not only in PostGIS itself on a technical basis but also in applying PostGIS and complementary tools in the real world. Their experiences are woven into the text which makes it an entertaining read at times - if you have been working on GIS projects you will instantly feel at home.

More importantly, highlighted tips spread throughout the book. These tips contain different types of hints: Which versions of tools work together and where to expect issues, what changed (or is bound to change) in different PostGIS versions, programming tips or shortcuts and background information on technical terms. Especially in the Performance Tuning section, these hints can save you days (both during development and at runtime).

I also particularly liked the layout and style of the code snippets and how they are commented and the focus on open source tools and how they compare to their proprietary counter parts.

This is not a book you need to read front to back. Once you are through with the introductional chapters, it can also be used as a kind of cookbook or to quickly dive a little deeper into one topic when needed.

As said in the one minute bottom line: If you are working with PostGIS or planning to do so, this book should be on your desk.

About the authors

Regina Obe and Leo Hsu work as database consultants. Both are active members of the PostGIS and Postgres communities. They share their experience on the project's mailing lists and wikis as well as on http://www.postgresonline.com and http://www.bostongis.com. Regina is a committer on the PostGIS project and member of its steering committee.