GPS for Dummies.pdf - Engineering Surveyor

Chapter 13: On the Ground with Maptech Terrain Navigator223The Topo USA maps are vector-based (drawn with lines and shapes), sothey don’t have the crisp appearance of a USGS digital raster map. However,DeLorme vector maps tend to have more updated road information becausesome of the scanned raster maps are based on data from maps made over 20years ago.3-D TopoQuads3-D TopoQuads provides more detailed maps that are sold by state or region.The maps are displayed as vector maps until you zoom in far enough, andthen they become 1:24,000 scale USGS scanned digital raster maps. (See anexample of a map, including 2-D and 3-D views, in Figure 13-8.)National Geographic mapping productsMany children got their first introduction to maps from National Geographicmagazines. Each month, a carefully folded paper map of somewhere foreignand exotic came nestled inside the magazine. National Geographic is still inthe map business, now producing several topographic map programs.Figure 13-8:2-D and 3-Ddisplay of1:24,000topographicmaps in 3-DTopoQuads.