Quads, or quadrangles, generally refer to USGS maps that cover 7.5 arc minutes (one minute of arc is equal to one-sixtieth of a degree). Basically each quad covers an area between 49 and 70 square ...

The maps in question are historical topographic maps of the US from the USGS’s vast collection. USGS topoView. The maps can be downloaded in various formats, including KMZ for viewing in Google ...

Adding TOPO! to Magellan's eXplorist GPS devices provides map detail levels including USGS 1:100,000-scale topographic, ideal for planning and visualizing long trips, and USGS 1:24,000-scale ...

Seamless Topographic USGS maps. November 30, 2011. A few months ago we showed you Matt Fox’s excellent topographic maps of New Zealand, which were quite impressive.