---
title: "Scale of a map and its classification"
subject: "Surveying I"
chapter: 1
key: "semester_3/surveying_i:scale-of-map-classification"
source: https://www.bctengineer.com/q/semester_3/surveying_i/scale-of-map-classification
site: BCT Engineering
---

# Scale of a map and its classification

Surveying I · Chapter 1: Introduction

- Asked in: 2078 Bhadra, 3 marks
- Video: [S2. Types of Scales in Surveying: Everything You Need to Know!!](https://www.youtube.com/watch?v=kEloy07QSCk) — Techsavvycivilengineers
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/surveying_i/scale-of-map-classification
- Whole chapter: https://www.bctengineer.com/md/semester_3/surveying_i/chapter-1

## Question

Explain 'Scale of a Map' and how the scale is classified and what its range of values is.

## Short answer

Scale is the ratio of map distance to ground distance. It is classified by expression as numerical, verbal, or graphical. By size, large scale ranges from 1:500 to 1:10,000, medium from 1:10,000 to 1:100,000, and small scale is smaller than 1:100,000.

## Answer

The **scale of a map** is the ratio between a distance measured on the map and the corresponding distance on the ground:

$$
\text{Scale (RF)} = \frac{\text{map distance}}{\text{ground distance}} \quad (\text{same units})
$$

For example, 1:50,000 means 1 cm on the map = 50,000 cm = 500 m on the ground.

#### Classification
**By the way it is expressed**
1. Numerical scale or RF (e.g. 1:25,000).
2. Verbal (statement) scale (1 cm = 250 m).
3. Graphical scale (bar, plain, diagonal, vernier).

**By size (range of values)**

| Class | Range of scale | Use |
|---|---|---|
| Large scale | 1:500 to about 1:10,000 | Detailed plans, cadastral, engineering design |
| Medium scale | 1:10,000 to about 1:100,000 | Topographic maps, regional planning |
| Small scale | Smaller than 1:100,000 | Atlas, general and index maps |

A larger denominator gives a smaller scale. A large-scale map shows a small area in great detail; a small-scale map shows a large area with few details. In Nepal, cadastral maps are 1:500 to 1:2500 and topographic maps are 1:25,000 and 1:50,000.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Scale (RF) is
   A. ground distance divided by map distance
   B. map distance divided by ground distance in the same units
   C. map area plus ground area
   D. the length of the sheet
   Answer: B. RF = map distance / ground distance. (Key point: Definition)

2. 1:50,000 means 1 cm on the map equals
   A. 500 m on the ground
   B. 50 m
   C. 5 km
   D. 50,000 m
   Answer: A. 50,000 cm = 500 m. (Key point: Calculation)

3. A map at 1:500 is classed as
   A. small scale, atlas use
   B. medium scale topographic
   C. large scale, giving detailed plans
   D. no scale
   Answer: C. Large scale: 1:500 to about 1:10,000. A larger denominator gives a smaller scale. (Key point: Classification)

## Related in Surveying I

- [Diagonal scale: Kathmandu-Pokhara highway map](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Adiagonal-scale-kathmandu-pokhara-224) — Surveying I, chapter 1, asked 2×
- [Scale for 1.5 km road on map](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Ascale-road-1-5-km) — Surveying I, chapter 1
- [RF and scale for 51072 m² plot](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Ascale-plot-51072-sqm) — Surveying I, chapter 1, asked 3×
- [RF and scale for 6.304 ha plot](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Ascale-plot-6-304-ha) — Surveying I, chapter 1, asked 3×
- [RF and scale for 51750 m² plot](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Ascale-plot-51750-sqm) — Surveying I, chapter 1, asked 3×
- [Criteria for selecting a suitable scale](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Acriteria-selecting-scale) — Surveying I, chapter 1, asked 2×

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