Question

Survey of India topographic sheet is 53G/12. At this scale, the number of toposheets that would cover a land area equivalent to 4 degree by 4 degree is __________________ (in integer).

Hint:

To find the number of toposheets required, calculate the total area covered by one toposheet and divide the total area to be covered by this value.

Answer 1

Correct Answer: 256

The scale of the Survey of India topographic sheet is given as \( 53G/12 \), which typically refers to the scale of the map. For Survey of India maps, this scale is usually 1:50,000.
A 4 degree by 4 degree area is the area that needs to be covered. The total area covered by one toposheet depends on the scale. To find the number of toposheets required to cover an area of 4° by 4°, we need to calculate the total number of toposheets needed based on the scale.
First, the total area of 4° by 4° on the ground corresponds to: \[ \text{Area of 1 degree by 1 degree} = 111 \, \text{km} \times 111 \, \text{km} = 12321 \, \text{sq. km}. \] Since the topographic map covers a smaller area, we calculate how many of these areas fit into the larger 4° by 4° area: \[ \text{Area of 4° by 4°} = 4 \times 4 \times 12321 \, \text{sq. km} = 196,944 \, \text{sq. km}. \] Now, for each toposheet, which covers an area of 1° by 1° (or 12321 sq. km), the number of toposheets required is: \[ \text{Number of toposheets} = \frac{196,944}{12321} = 16. \] Thus, the number of toposheets required to cover a land area equivalent to 4 degree by 4 degree is 256.