Nathan Jennings is a full-time GIS professional with the City of Sacramento and for a number of years has taught as an Adjunct GIS Professor at American River and Sacramento City Colleges in the Los Rios Community College system in Sacramento as well as Sierra College in Rocklin, CA, the UC Davis Extension Program in Davis, CA and is an Adjunct Professor with Del Mar College in Corpus Christi, TX where he teaches online Open Source GIS courses. He also operates Urbandale Spatial, a geospatial consulting firm, in the Sacramento, CA area. Mr. Jennings has designed and currently teaches courses in GIS programming, remote sensing, web map application development, and GPS. He has authored A Python Primer for ArcGIS(R) Workbook series to help those who wish to better understand ArcGIS functionality using Python. www.urbandalespatial.com