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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 ...
The United States remains virtually the only developed country in the world without a standardized civilian topographic map series in the standard 1:25,000 or 1:50,000 metric scales, making coordination difficult in border regions (the U.S. military does issue 1:50,000 scale topo maps of the continental United States, though only for use by ...
Shaded relief map of the United States, showing 10 geological provinces. The richly textured landscape of the United States is a product of the dueling forces of plate tectonics, weathering and erosion. Over the 4.5 billion-year history of the Earth, tectonic upheavals and colliding plates have raised great mountain ranges while the forces of ...
The elevation of a geographic area may be stated in several ways. These include: The maximum elevation of the area (high point); [a] The minimum elevation of the area (low point); [b] The arithmetic mean elevation of the area (statistical mean elevation); [c] The median elevation of the area (statistical 50% elevation); [d] and; The elevation ...
In aviation, the term elevation or aerodrome elevation is defined by the ICAO as the highest point of the landing area. It is often measured in feet and can be found in approach charts of the aerodrome. It is not to be confused with terms such as the altitude or height. [1] Part of a topographic map of Haleakala , showing elevation.
A map of Europe using elevation modeling. In its contemporary definition, topographic mapping shows relief. In the United States, USGS topographic maps show relief using contour lines. The USGS calls maps based on topographic surveys, but without contours, "planimetric maps."
The exact definition and reference datum varies according to the context (e.g., aviation, geometry, geographical survey, sport, or atmospheric pressure). Although the term altitude is commonly used to mean the height above sea level of a location, in geography the term elevation is often preferred for this usage.
The National Elevation Dataset (NED) consists of high precision topography or ground surface elevation data (digital elevation model) for the United States. It was maintained by the USGS and all the data is in the public domain. Since the 3D Elevation Program came online, the NED was subsumed [1] into The National Map as one of its layers of ...