Writing, developed first by people in Sumer, is considered a hallmark of civilization and appears to accompany the rise of complex administrative bureaucracies or the conquest state. Traders and bureaucrats relied on writing to keep accurate records.
Elevation, or geometric height, is mainly used when referring to points on the Earth 's surface, while altitude or geopotential height is used for points above the surface, such as an aircraft in flight or a spacecraft in orbit, and depth is used for points below the surface. topographical map is the main type of map used to depict elevation, often through use of 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.
The complementary angle of a latitude is called the colatitude. â¢ Altitude is the elevation of a point or object from a known level or datum. Common data are mean sea level, local ground level (Above Ground Level, or. AGL), or the surface of the WGS-84 geoid, used by GPS. In aviation, altitude is.