Scale

Scale, in cartography, the ratio of the distance between two points on a map and the actual distance between the two points on the Earth's surface. On maps, scale is represented in three ways: as a ratio or fraction, such as 1:50,000 or 1/50,000, which means that 1 unit of measurement on the map equals 50,000 of the same units on the Earth's surface; as a graphic scale, usually a straight line on which distances (most often in kilometres or miles) have been marked off; and as a phrase in words and figures, such as “1 cm represents 100 km” (that is, 1 cm on the map represents 100 km on the Earth's surface). The larger the scale of a map, the closer it approaches the actual size of features on the Earth's surface. Small-scale maps generally show larger portions of the Earth's surface and have less detail than large-scale maps. Because maps are flat and the Earth’s surface is curved, scale may vary within a single map; the scale expressed in the legend is generally accurate near the centre of the map, but less so towards the edges.