Question

What is the actual distance between two places that are 20 cm apart on a toposheet with a scale of 1:50,000 ?

• A. 20 km
• B. 2 km
• C. 10 km
• D. 5 km

Answer 1

Answer:

C. 10 km

• Toposheets (Topographical Maps): These maps display physical and cultural features of an area using contour lines and symbols. In India, these are published by the Survey of India.

• Scale Types: Maps generally use three types of scales: Statement of Scale (e.g., 1 cm to 1 km), Representative Fraction (RF) (e.g., 1:50,000), and Graphical or Linear Scale (a line divided into parts).

• Standard Toposheet Scales: Common scales used for topographical mapping are 1:25,000, 1:50,000, and 1:250,000. The 1:50,000 scale is the standard series provided by the Survey of India for detailed planning and fieldwork.

• Scale Definition: A representative fraction (RF) scale of 1:50,000 means that 1 unit on the map represents 50,000 units of the same measurement in reality.

• Step 1: Convert the map distance to actual distance in the same unit. 20 cm × 50,000 = 1,000,000 cm.

• Step 2: Convert centimeters to meters. Since 100 cm = 1 m, divide by 100: 1,000,000 cm / 100 = 10,000 meters.

• Step 3: Convert meters to kilometers. Since 1,000 m = 1 km, divide by 1,000: 10,000 m / 1,000 = 10 km.