1. Colour tints
- Yellow: cultivated land. Green: forest (and orchards). White: uncultivated land such as open scrub or barren ground.
- Blue: water (streams, tanks, canals). Brown: relief, shown by contours. Black: man-made features: huts, tracks, names. Red: metalled roads. Real Survey of India sheets differ in some details (for example the colour of grid lines and settlements); follow the key printed on the sheet you are given.
- On the imagined practice sheet (not a real place, not a Survey of India sheet) about 45% of the area is cultivated, 33% open scrub and 22% forest.
- Always read the key of the sheet.
| Colour | Shows |
|---|---|
| Yellow | Cultivated land |
| Green | Forest |
| White | Uncultivated land |
| Blue | Water |
| Brown | Contours |
| Red | Metalled roads |
Key terms
- Key (legend)
The list of symbols and tints used on a sheet, with their meanings.
- Tint
A colour wash that shows a kind of land cover.
2. Conventional symbols: points
- Huts: small black squares (clustered in a village or dispersed).
- Temple: flag on a square. Well: circle with a dot. Tank: blue shape.
- PO post office, PS police station, Dis dispensary.
- Triangulated height: black triangle with a figure. Spot height: black dot with a figure.
| Symbol | Feature |
|---|---|
| Black squares | Huts |
| Flag on a square | Temple |
| Circle with a dot | Well |
| PO, PS, Dis | Post office, police station, dispensary |
Key terms
- Conventional symbol
A standard sign that shows an object on a map without drawing it to scale.
3. Conventional symbols: lines
- Metalled road: thick red line. Unmetalled road: thick black broken line. Cart track: thin black line. Pack track: thin broken line. Footpath: dotted line.
- Perennial stream: continuous blue line. Seasonal stream: dashed blue line. Canal: thick blue line along a contour. Embankment: line with short ticks. Bridge: short thick bar across the river.
| Line | Meaning |
|---|---|
| Thick red | Metalled road |
| Dotted black | Footpath |
| Dashed blue | Seasonal stream |
Key terms
- Metalled road
A road with a hard surface of stone or tar, shown in red.
- Seasonal stream
A stream that carries water only in the rains, shown by a dashed blue line.
4. Scale
- Statement scale: in words (1 cm to 0.5 km). Representative fraction (RF): a ratio with no units (1 : 50 000). Linear scale: a bar marked in km.
- Statement scale to RF: convert the ground distance to cm. 0.5 km = 50 000 cm, so RF 1 : 50 000.
- RF to statement: 1 : 25 000 means 1 cm to 25 000 cm = 0.25 km.
- 1 km = 1 000 m = 100 000 cm. On the imagined sheet one grid square (1 km) is 2 cm.
| Scale | Value |
|---|---|
| Statement | 1 cm to 0.5 km |
| RF | 1 : 50 000 |
| Linear | Bar of 5 km |
Key terms
- Representative fraction
The scale written as a ratio without units, such as 1 : 50 000.
- Linear scale
A bar divided into ground distances, usable at any enlargement.
5. Distance and area
- Distance: only the straight-line (direct) distance is measured. Measure in cm and multiply by 0.5 km per cm. For example 1.8 cm is 0.9 km. A check from the grid: distance = square root of (east-west difference squared plus north-south difference squared).
- Area: count only complete 1 km squares; each is 1 sq km. A block 3 squares by 3 squares has 9 sq km. Part squares are not counted.
| Item | Method |
|---|---|
| Distance | cm times 0.5 gives km |
| Area | Number of full squares gives sq km |
Key terms
- Direct distance
The straight-line distance between two places, not along a road or river.
6. Direction
- Eight points: N, NE, E, SE, S, SW, W, NW (45 degrees apart). North is at the top of a sheet unless an arrow shows otherwise.
- Give the direction from the first place to the second. Reversing the places gives the opposite point (NE becomes SW).
- On the imagined sheet the temple is north-east of the dispensary and about 3.8 km away; the police station is south of the temple.
| Point | Opposite |
|---|---|
| North-east | South-west |
| North-west | South-east |
| North | South |
| East | West |
Key terms
- Intercardinal points
North-east, south-east, south-west and north-west, between the four cardinal points.
Exam tips
Common mistakes
- Writing units in an RF, or forgetting to convert km to cm.
- Measuring distance along a road instead of the straight line.
- Counting part squares when finding area.
- Giving a direction from the second place to the first.
- Confusing seasonal (dashed) and perennial (continuous) streams.
How marks are usually awarded
- Colour or symbol (1 mark): the feature, not just the colour.
- Scale (1 to 2 marks): the unit conversion shown and the RF written correctly.
- Distance, area (2 marks): working and unit.
- Direction (1 mark): one of the eight points.