Cartometry

the division of cartography in which methods of measurement of various geographic objects on maps to find their area, length, volume, and other quantitative characteristics are studied. Direct measurement of the length and area of actual objects using geodetic methods can only be done when the objects have very small dimensions. Cartometry is concerned with the computation of larger quantities, such as the areas of states and oceans, the lengths of coastlines and rivers, and the areas of river drainage basins. It also includes methods for the computation of various quantitative characteristics of terrain (average elevation, average angle of slope, volume, and density of the river network) by measurement on maps.