Introduction and Finding Scale of Map from R.F value

1. A map is a scale drawing of the actual shape of a piece of land. The area of the land on the map is many times smaller than the actual area. 
2.The scale of a map is usually given at the bottom corner of the map. The scale is the ratio of the distance on the map to the actual distance on the ground.

The scale of a map (linear scale) is given in the form 1 : n or 1/n. 
It means that 1 unit length on the map represents n units on actual ground. 
E.g. a map is drawn to a scale of 1 cm to 5 km. This scale can be expressed as 1 : 500 000 or 1/500 000. The scale means that 1 cm on the map represents 500 000 cm on actual ground. 

The scale 1 : n can also be expressed as a representative fraction (R.F.) of 1/n. Here, the numerator of the fraction is always 1. 
E.g. The scale 1 : 300 can be expressed as a representative fraction of 1/300. 
E.g. If the representative fraction is 1/200, the scale would be 1 : 200.

The following image is a worked example of how Map Scale is used in questions and answers. 

Finding R.F. from Scale of Map

Besides having to find map scale from R.F. value, questions may ask for the R.F. to be found when given a map as well. The following is a worked example of how such questions can be solved:

Area Scale

1. The area scale of a map is the square of its linear scale. If the linear scale is 1 : n, then the area scale is 12 : n2, i.e. 1 : n2. 
E.g. If the scale of a map is 1 cm to 3 km, then 1 cm2 on the map will represent (3 km)2, 9 km2. 
Hence the area scale is 1 cm2 to 9 km2 while the linear scale is 1 cm to 3 km. 

The following video is a worked example of a question involving map and area scale.

Worked Example

View the following worked example: