Geography [2 Mark Question Answer]

Rivers generally rise on slopes and are joined by a large number of other small rivers or streams. The entire area drained by a rivet and its tributaries is called a river system.

The use of various colours are essential to show the various features on the toposheet e.g. the cultivated area is always shown by the yellow colour and the green colour on the toposheet, shows the forested and wooded area.

Grid lines are imaginary lines drawn on a survey map in red colour. The origin of the Grid is a point south-west of the map. The ‘National Grid Reference’ is used for indicating the correct position of a particular feature on the map.

A Grid is a set of lines used to find the exact location of places on a map. Most maps use the grid formed by latitudes and longitudes to find places.

Land varying between 20 metres to 40 metres above sea level, is called flat land. This type of area has sufficient slope for natural drainage. This area is generally suitable for farming.

Some methods by which directions can be located are:
(i) Angular Bearing    
(ii) By Magnetic Compasa
(iii) The Pole Star        
(iv) Sunrise and Sunset.

Since mapping is primarily a science of whereabouts a student of geography should, therefore, be familiar with directions and also the methods of finding out directions on different occasions and in various circumstances.

If R.F., is 1 : 2,500,000 what is the scale (answer in centimetre and kilometre).
R.F. = `"Distance on the map"/"Distance of the ground"`
`= (1 "cm")/ 2500000`
`= (1 "cm")/ (25 "km")`

If a scale is 2 cm., to 1 km., calculate the R.F.
R.F. = `"Distance on the map"/"Distance of the ground"`
`= (2  "cm")/(1 "km") = (2 "cm")/(1000 xx 100  "cm")`
`= 1/ 50000 = 1 : 50000`

Three methods of indicating scale on maps are:
(i) By a statement
(ii) By representative fraction
(iii) By graphical scale or linear scale.

A scale is very essential for a map because it represents a large area of a country on a small piece of paper. A scale is the ratio between any two points on a map to the corresponding distance between the same two points on the actual ground.

A watershed or water divide is a ridge which separates the tributaries draining towards one side of it from those drawing towards the other. A watershed is never half way up a slope and on the two sides of it, the slope must be opposite and downwards.

Topographical map gives detailed information about physical features and man-made features of a small area. Physical features are depicted by contours. Cultural or man made features are represented by symbols called conventional signs.