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J <br /> Y <br /> Explanation of Terms <br /> Control - the use of existing or new USGS monuments to precisely tie-in locations on the ground to <br /> the photography being taken by the airplane. The airplane must have this information when it flies <br /> to register location values on the photos and its Global Positioning System (GPS) device which <br /> creates the accuracy of digital orthophotos,topography, and planimetrics at the highest level <br /> ("surveying standards"). <br /> Analytical - Fully Analytical Aerial Triangulation(FAAT) is the computer mathematical model that <br /> translates global positioning system(GPS), surveying, and monument values (X,Y Coordinates) <br /> into the creation of digital orthophotos from aerial photographs. It is the most crucial treatment of <br /> the scanned aerial photographs to create their accuracy (called "rectification" in the business). <br /> Orthophotos - computerized photographs, showing measurement and visualization of tree and other <br /> ground cover,presentations for public meetings,three dimensional rendering of views of the County <br /> with visual features displayed. <br /> Topography -refers to topography and elevation contours -planning, development and engineering <br /> analysis of floodplain, watershed and sewer issues are some of the applications that can benefit from <br /> this layer of GIS information. <br /> Planimetrics - refers to the built environment(as opposed to natural terrain). Planimetric maps <br /> showing building footprints, paved surfaces, surface water and other physical features can be used <br /> for planning,public safety applications, stormwater management and site analysis, to cite just a few <br /> examples. <br />