Scale is an essential element in all types of maps.
A network of lines and polygons in the absence of scale is known as sketch.
Scale is used to find out the ground distance on the map. It provides the relationship between a map and the whole or a part of the earth’s surface shown on it.
Scale is the ratio between a distance measured on a map and the corresponding distance on the earth’s surface.
A scale is expressed by the metric system of measurement and the English system of measurement.
Metric system has units of measurement like kilometer, centimeter, metre, etc. This system is presently used in India and in many other countries.
English System contains units like mile, furlong, yard, feet, etc. This system is prevalent in the United States and the United Kingdom.
There are three types of scale:
Graphical scale, and
In Statement Scale, the scale of a map is indicated in the form of written statement.
Graphical or Bar scale shows map distances and the corresponding ground distances using a line bar.
Representative Fraction (R.F.), shows the scale of a map as a fraction or ratio. The numerator represents the map distance and the denominator represents the corresponding ground distance on this map.
Map scales can be converted from one to another according to the user’s need.