Distance is the length of elongated features on the earth’s surface such as road, railway, river etc. How to measure distance. In order to obtain distance of any feature on the map, consideration should be made on whether the distance to be measured is straight or curved.
Straight distance For all straight distances a ruler is used to obtain the distance directly from the topographical map given. Curved distance. It becomes difficult to obtain curved distance of the features by the use of a ruler directly from the topographical map when the area is inclined. In this case the following devices can be used:-
(a) A pair of divider: A pair of divider is commonly used to measure the distance. You should start by breaking the length by using a pair of dividers then transfer some of the already drawn straight lines. Then transfer the measured line to the linear scale or ruler for calculation to get the actual distance.
(b) A piece of a string: Slowly measures the distances by a piece of string along a given length then transfer it to a linear scale or ruler for actual calculation of the distance.
(c) A piece of strip paper: Slowly lay a piece of paper along a given length then break your lengths into short segments then transfer to the linear scale for measuring and calculation.