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Topographic maps are also commonly called contour maps or topo maps. In the United States, where the primary national series is organized by a strict 7.5-minute grid, they are often called or quads or quadrangles. Topographic maps conventionally show topography, or land contours, by means of contour lines.
While not officially "topographic" maps, the national surveys of other nations share many of the same features, and so they are often called "topographic maps." Existing topographic survey maps, because of their comprehensive and encyclopedic coverage, form the basis for much derived topographic work. Digital Elevation Models, for example, have ...
The United States Geological Survey (USGS) topographical survey maps included contour representation of relief, and so maps that show relief, especially with exact representation of elevation, came to be called topographic maps (or "topo" maps) in the United States, and the usage has spread internationally.
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". A quadrangle is defined by north and south boundaries of constant latitude (which are not great circles so are curved), and by east and west boundaries of constant ...
The Centre for Topographic Information produces topographic maps of Canada at scales of 1:50,000 and 1:250,000. The full map catalogue is known as the National Topographic System (NTS). [ 16 ] A government proposal to discontinue publishing of all hardcopy or paper topographic maps in favor of digital-only mapping data was shelved in 2005 after ...
Mairie de Loevenich (), from the Topographic Survey of the Rhineland by Tranchot/Müffling, sheet 57 (published 1806/07).. A map series is a group of topographic or thematic charts or maps usually having the same scale and cartographic specifications, and with each sheet appropriately identified by its publisher as belonging to the same series.
In cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. [3] A contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes. [4]
The National Map is part of the USGS National Geospatial Program. [3] The geographic information available includes orthoimagery (aerial photographs), elevation, geographic names, hydrography, boundaries, transportation, structures and land cover. The National Map is accessible via the Web, as products and services, and as downloadable data ...