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A "quadrangle" is a topographic map produced by the United States Geological Survey (USGS) covering the United States. The maps are usually named after local physiographic features. The shorthand " quad " is also used, especially with the name of the map; for example, "the Ranger Creek, Texas quad".
USGS topographic quadrangle maps are marked with grid lines and tics around the map collar which make it possible to identify locations on the map by several methods, including the graticule measurements of longitude and latitude, the township and section method within the Public Land Survey System, and cartesian coordinates in both the State ...
A digital orthophoto quadrangle [1] (DOQ) is aerial photography or satellite imagery that has been corrected so that its pixels are aligned with longitude and latitude lines, and have a narrowly defined region of coverage. This is a widely used format introduced by United States Geological Survey (USGS). [1]
The USGS also utilizes data from The National Map Corps, which consists of volunteers who devote some of their time to provide cartographic information on structures. [4] The National Map is the official replacement for the USGS topographic map program. [5]
The USGS Library’s map collection contains a broad collection of maps covering the United States, foreign areas, and planetary bodies. The collection includes topographic maps, geologic maps, and thematic maps concentrating on the geosciences.
A small portion of a USGS DRG. A digital raster graphic (DRG) is a digital image resulting from scanning a paper USGS topographic map for use on a computer. DRGs created by USGS are typically scanned at 250 dpi and saved as a TIFF. The raster image usually includes the
USGS Topographic maps are downloadable as pdf files from a searchable map or by a search if the map name is known. How a Topographic Map is Manufactured, History, and Other Information The International Cartographic Association (ICA) Commission on Topographic Mapping
Figure 1. This BLM map depicts the principal meridians and baselines used for surveying states (colored) in the PLSS.. The following are the principal and guide meridians and base lines of the United States, with the year established and a brief summary of what areas' land surveys are based on each.