Book Review: Desktop GIS – Mapping The Planet With Open Source Tools by Gary E. Sherman

Geographic Information Systems (GIS) is fast becoming the de facto tool of choice for mapping and managing spatial information. The beauty of GIS is its ability to store an almost infinite amount of data within specific feature sets or attributes (i.e. county, city, block, river, etc.).

Environmental Systems Research Institute, Inc. (ESRI) is the leading company that develops ArcGIS, which is the dominant suite of applications and software that many government agencies and academic departments use to do their research. ESRI's ArcGIS is cheap, and many dedicated software developments have taken it upon themselves to create open source GIS tools.

Gary E. Sherman's new book Desktop GIS: Mapping The Planet With Open Source Tools attempts to bridge the gap between the mountains of literature on ArcGIS and plains of open source GIS. Sherman tries to strike the balance between introducing novice users to GIS and showing intermediate Arc users open source GIS, but ultimately the end result is a brisk look at how one can use open source tools to analyze geospatial data.

The first couple of chapters provide brief introductions into the open source software (GRASS, Quantum GIS or QGIS, uDig) Sherman will be using in his book.

He also provides a frustratingly small list of reliable and trusted data sources like the Federal Geographic Data Committee's (FGDC) clearinghouse network or Geodata. One of the harder aspects of GIS is simply finding data, to which Sherman glosses over: "There are a lot of sources for data on the Internet, and a bit of judicious searching can lead to good finds" (p. 25). Thankfully he forwards users to the supplemental website that doesn't provide much in extra resources.

The next few chapters deal with basic functions like working with vector layers, shape files and their attribute data, and working with rendering settings to get the map to display how you want it to look. Sherman does a very good job providing easy-to-understand summations of raster data, data formats, map projections, and databases (the latter which can be pretty technical and be better learned in more depth).

Desktop GIS is meant to introduce tools for people to use, but the few chapters that actually describe how to use GIS are surprisingly short. Chapter eight ("Creating Data") deals with (as the title states) creating your data through heads-up digitizing or GPS data collection. Chapter 10 ("Geoprocessing") deals with the more meatier data analysis that makes GIS so efficient and useful. Chapter eight is a scant 17 pages while Chapter 10 is only 25. Learning about GIS modules like buffers and overlays is scattered in Chapter 12 ("Getting The Most Out Of QGIS And GRASS Integration").

The latter chapters are even more technical as they pertain to command-line techniques, GDAL/OGR (I still don't know what these are), and creating your own custom applications. Arguably the most useful part of the book is the Appendices, which lays out GIS in straightforward and distinct sections. There is also a section detailing the pros and cons of each GIS software the author uses.

Thankfully, Desktop GIS is in color, which makes the screenshots and images easy to read. Unfortunately, sometimes the pages don't have the best layouts so the images need to be sought after instead of being on the same page they are referred to, as with Figure 3.16 located on page 48 but referred to on page 45. It doesn't happen often but it can be annoying, especially since the book reads as a tutorial.

I would have liked to see in the Appendices is a glossary section. There is so much terminology that it would have been helpful to have a one-stop place to catch up on those unfamiliar words without having to search for it on earlier pages.

Sherman goes through a few analysis projects throughout Desktop GIS, but I would have liked to see him provide a complete tutorial for one project from start to finish. Many of the tools are mentioned sporadically, so showing the reader a more realistic run through a "typical" analysis would have been very helpful. Sherman could also go a step further and provide short video clips on the website.

Desktop GIS provides the basic functions of open source GIS tools in brief yet comprehensive manner. Novice users will benefit from the easy-to-follow text and images, while intermediate users might only look at certain sections to get the ArcGIS equivalents.