Sonoma County California USGS Topographic Maps on CD All the USGS 1:24,000 scale quadrangle maps for your County have been merged together to create this seamless map CD. Easy to use - No experience needed. Free GIS viewer software -Windows 98/2000/NT/XP/Vista/Win7. MAC users must run under windows dual boot. Zoom, pan, measure, copy/paste into reports, and print your own maps. No need to carry multiple USGS maps anymore. Print just your area, even if it falls on the corner of the original paper map. Our digital maps do not have corners or edges. No restrictions of use. Commercial use is allowed. Use in publications, websites, & maps/posters. You get full utility of the data - not just a jpg snapshot!