MAP SCALE is the proportion or ratio between the distance to two points on a map and the actual distance it represent on the ground.
It can also mean the relationship between a linear measurement on a map and the actual measurement on the earth’s surface (i.e. the ground 1 For instance, if the scale of a map is one centimetre to one centimetre. it means that every one centimetre on a map represents ccc Kilometre on the ground.
Types of Map Scales
Representative Fraction Scale (RF): under this type of scale the distance on a map and the distance on the ground are expressed in either ratio or fraction form.
i.e. Length on Map = 1 or 1.100,000
Distance on ground 100,000
Thus, the RF of 1cm to 1km could be written either as fraction or ratio as above. Note that the numerator, which is 1. represents the length while the denominator, which is 100.000. represents the actual distance on the ground.
Statement Verbal Scale: Under this type of scale. the relationship or ratio between the distance of a map and the actual distance it represents on the ground are expressed in words and figures. For example, 1cm represents 1km. This means 1cm on the map is represented by 1km on the ground.
Linear Scale: This is also known as graphic or line scale. As the name implies, it is a line drawn to represent the relationship or ratio between the distance on a map and that of the actual distance on the ground. In this type of scale, the line drawn is divided into two Primary and Secondary divisions as shown below:
In the above graph, the primary divisions starts fairly long right and are used to measure fairly long distances while the secondary division starts from the left of Zero and are used to measure short distances such as fractions of Km linear scale could be open-divided. Double Unit or filled linear scale.