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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.
Example of topographic profile. A topographic profile or topographic cut or elevation profile is a representation of the relief of the terrain that is obtained by cutting transversely the lines of a topographic map. Each contour line can be defined as a closed line joining relief points at equal height above sea level. [1]
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.
Digital Elevation Models, for example, have often been created not from new remote sensing data but from existing paper topographic maps. Many government and private publishers use the artwork (especially the contour lines) from existing topographic map sheets as the basis for their own specialized or updated topographic maps. [9] Topographic ...
A topographical map is the main type of map used to depict elevation, often through contour lines. In a Geographic Information System (GIS), digital elevation models (DEM) are commonly used to represent the surface (topography) of a place, through a raster (grid) dataset of elevations. Digital terrain models are another way to represent terrain ...
Not all National Topographic System maps strictly follow the National Tiling System's linear grid. Some maps also, as an "overedge", cover land in an area which would otherwise be covered by an adjacent map sheet, simply because the latter area does not contain enough land in Canada to warrant a separate printing. [4] [clarification needed]
A topographic map of Ngorongoro Crater in northern Tanzania, the world's largest inactive, intact, and unfilled volcanic caldera, which formed when an immense volcano erupted and collapsed on itself 2–3 million years ago. The floor of the caldera is 600 metres (2,000 ft) below its rim and covers more than 260 square kilometres (100 sq mi).
The National Map is a significant contribution to the U.S. National Spatial Data Infrastructure (NSDI) from the Federal Geographic Data Committee (FGDC) and currently is being transformed to better serve the geospatial community by providing high quality, integrated geospatial data and improved products and services including new generation ...