Gorr L. Wilpen  <br/><br/>
Learning and using Geographic information systems:  ARCGIS Edition 
Gorr L. Wilpen 
 - Canada  Thomson course technology  2007 
 - 349 p.  Index, p 341-349 
<br/><br/><label>ISBN: </label>978-1-4188-3558-3 
<br/><br/><label>Subjects--Topical Terms: </label>--Geography
<br/><br/><label>LC Class. No.: </label>G 70.212  / :G74 2007