What is the common scale adopted in the form of a representative fraction for a forest map?
Correct Answer:
C. 1/25000
📝 Detailed Explanation: Understanding Map Scales
The scale of a map is the ratio of a distance on the map to the corresponding distance on the ground. A Representative Fraction (RF) is a common way to express this scale, where the numerator is always 1.
A forest map is a specific type of topographical map, which shows detailed features of a land area. Based on standard surveying conventions, topographical maps have a specific range of scales. The correct answer is 1/25000 because it falls within the standard scale for topographical surveys.
Common Scales for Different Survey Types
The table below lists the generally accepted scales for various types of maps and surveys. This helps in selecting the appropriate level of detail for a project.
| Type of Survey / Map | Representative Fraction (RF) |
|---|---|
| Geographical Maps | 1/500000 to 1/15000000 |
| Topographical Maps (including Forest Maps) | 1/25000 to 1/250000 |
| Land (Cadastral) Survey | 1/500 to 1/5000 |
| Route Survey | 1/10000 |
| Town Planning | 1/10000 |
| Building Map | 1/1000 |
💡 Key Concepts for Students
- Representative Fraction (RF): RF = (Distance on Map) / (Distance on Ground). For an RF of 1/25000, it means 1 unit of length on the map represents 25,000 of the same units on the ground.
- Large Scale vs. Small Scale: A map with a smaller RF denominator (e.g., 1/500) is a "large-scale" map and shows more detail for a small area. A map with a larger denominator (e.g., 1/1,000,000) is a "small-scale" map and shows less detail for a large area.
- Map Purpose Dictates Scale: The choice of scale directly depends on the map's purpose. A detailed building plan requires a large scale, while a geographical map of a whole country uses a very small scale.