Gary E. Sherman — Desktop GIS: Mapping The Planet With Open Source Tools

Gary E. Sherman - Desktop GISGeo­graphic 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 isn’t 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 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) he 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 8 (“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 8 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 he uses.

Thank­fully, the book 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 Sher­man 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. He 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.

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