Representation of Geographical Features

(a) R.F. stands for representative fraction.

(b) We follow metric system to measure distances in India.

(c) A map is more accurate than a globe.

(d) A verbal scale is less popular than linear scale.

(e) Distance is measured in kilometres or metres.

(a) Verbal scale — In this method the scale is expressed in words, e.g., 1 cm on the map represents 50 km on the ground. This method is not very popular as it does not give the accurate measurement.

(b) Graphic scale — This scale represents the relationship between the distance on the map and distance on the ground. It is drawn according to the statement in such a way that the distance can be calculated most accurately on the map.

(c) Scale — Scale can be defined as a ratio between a distance measured on a map and a corresponding distance on land, connecting the two points represented by the same unit.

(d) RF — The numerical fraction/ representative fraction is the method of measuring distance that shows the ratio between the distance on the map to the distance on the ground.

(a) Causeway — It is a raised road or platform across a minor stream that is motorable during dry season.

(b) Brackish — The well whose water is unfit for drinking and cultivation as it is salty is said to be brackish.

(c) Meander — It is a bend in the river flowing through a plain. Its presence indicates a flat land.

(d) Contours — These are lines shown in brown, joining places of equal height above the sea level.

The advantages of drawing a map to scale are:

1. A scaled map accurately represents the relative sizes and distances of geographic features, ensuring that they are portrayed in proportion to each other as they exist in reality.
2. When a map is drawn to scale, it allows for precise measurements of distances, areas, and angles which is useful for military purposes, town planners, surveyors, engineers, geographers, geologists, etc.
3. Scale is useful to depict the geographical features e.g., large scale map depicts the geographical features of small area in detail. Small scale maps show only the important features of a large area.

Topographical maps portray natural features, man-made features and cultural features using appropriate colours. Each colour used on maps has its own significance. For example, yellow is used to show cultivable land, plateaus, deserts and plains, green is used for forest area or lowland areas.
The colours are universally accepted both for interpretation of survey sheets and map pointing.

The two ways to measure distances are:

1. Measuring distances in a straight line or as the crow flies
   1. As the crow flies, refers to the shortest distance between two given points.
   2. Distance can be measured directly by using the scale or with the help of a divider.
2. To measure the distance of a curved road, river or canal:
   For this, the following methods are used:
   1. With the help of paper strip.
   2. With the help of a thread.

Topographical maps are based on accurate survey of the land. They show natural features of the ground like hills elevation, drainage, trees and vegetation as well as man-made features like towns, villages, buildings, roads, canals, railways, power transmission lines and other cultural features in detail. Due to this, two reasons that make them important are:

1. They are used for military purposes.
2. They serve as a guide for travel.

Distance

North

Yellow

White

Red

Grid

Small area

Map distance and ground distance

Crow flies

Metres

Metalled road

PTO

Canal

Dendritic

Fire line