LIWA

Interpretation of Topographical Maps

ICSE Class 10 · Geography · Chapter 1

What this chapter covers

Key definitions

Eastings are the vertical grid lines that run from north to south on a toposheet; their numbers increase towards the east.

Northings are the horizontal grid lines that run from west to east on a toposheet; their numbers increase towards the north.

Natural features are the features of a landscape that have been formed by nature without human effort, such as hills, valleys, rivers, streams, lakes, forests, sand dunes and marshes.

Relief features are the differences in height and shape of the land surface, such as hills, ridges, plateaus, valleys, plains and escarpments.

Drainage features are the rivers, streams, lakes and other water bodies of an area, together with the direction in which water flows.

Natural vegetation is the plant cover that grows in an area without being planted or tended by people.

Man-made features are the features of a landscape that have been built or created by people, such as settlements, roads, railways, canals, dams, wells, tanks, bridges, places of worship, power lines and survey marks.

Land use is the way in which people make use of a piece of land, such as for cultivation, settlement, transport, mining or recreation.

Land cover is the physical material found on the surface of the land, such as forest, grass, bare rock, sand, water or crops.

Fallow land is cultivable land that is left uncultivated for one or more seasons so that the soil can regain its fertility.

Metalled roads are roads with a hard, durable surface of crushed stone, tar or concrete, which can be used by heavy vehicles in all seasons.

Unmetalled roads are roads with a surface of beaten earth or gravel, which are cheaper to build but become muddy and difficult to use during the monsoon.

Key points

Questions answered

Define a topographical map.
A topographical map is a large-scale map that shows both the natural and the man-made features of a small area in great detail, using colours, conventional symbols and contours.
What are eastings and northings? Which one is written first in a grid reference?
Eastings are vertical grid lines whose numbers increase towards the east; northings are horizontal grid lines whose numbers increase towards the north. The easting is always written first.
A school lies in the square bounded by eastings 35–36 and northings 82–83. Give its four-figure grid reference.
3582 (easting 35 on the left, northing 82 below).
A bench mark lies 4 tenths east of easting 35 and 9 tenths north of northing 82. Give its six-figure grid reference.
354829.
Why is a six-figure grid reference more useful than a four-figure one?
A four-figure reference names a whole grid square (1 sq km on a 1:50,000 sheet), while a six-figure reference locates a point within about 100 m, so it can separate two similar features in the same square.
On a 1:50,000 sheet, what is the ground distance between 612 405 and 612 413?
The northing groups differ by 413 - 405 = 8 tenths, so the distance is 8 × 100 m = 800 m, due north–south.
Give two natural and two man-made features you would expect on a toposheet of a dry region.
Natural: a non-perennial river with a dry sandy bed; scrub or sand dunes. Man-made: wells; tanks.
Distinguish between a metalled road and an unmetalled road.
A metalled road has a hard surface of crushed stone, tar or concrete and can be used in all seasons by heavy vehicles; an unmetalled road has an earth or gravel surface and becomes muddy and difficult to use in the monsoon.