---
title: "Eight methods of linear measurement"
subject: "Surveying I"
chapter: 2
key: "semester_3/surveying_i:list-eight-linear-methods"
source: https://www.bctengineer.com/q/semester_3/surveying_i/list-eight-linear-methods
site: BCT Engineering
---

# Eight methods of linear measurement

Surveying I · Chapter 2: Distance Measurements

- Asked in: 2067 Asar, 4 marks
- Video: [Linear Measurement in Basic Civil Engineering](https://www.youtube.com/watch?v=zW4yiJkeb5I) — Engineering Funda
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/surveying_i/list-eight-linear-methods
- Whole chapter: https://www.bctengineer.com/md/semester_3/surveying_i/chapter-2

## Question

List eight methods of linear measurements.

## Short answer

Pacing, passometer/pedometer, odometer, chaining, taping, tacheometry (stadia), subtense bar, and electronic distance measurement (EDM).

## Answer

Eight methods of linear measurement are:

1. **Pacing:** distance = number of paces $\times$ average length of one pace. Rough, about 1/100 accuracy, used for reconnaissance.
2. **Passometer or pedometer:** a small instrument carried by the surveyor that records the number of steps.
3. **Odometer, measuring wheel (perambulator):** a wheel that records its revolutions; distance = revolutions $\times$ circumference. Used for road lengths.
4. **Chaining:** direct measurement with a metric chain (20 m or 30 m) for chain survey.
5. **Taping:** direct measurement with steel, invar or cloth tapes. Corrections are applied for high accuracy.
6. **Tacheometry (stadia):** the distance is calculated from the staff intercept between the stadia hairs and the vertical angle, using a theodolite.
7. **Subtense bar method:** a bar of fixed length (e.g. 2 m) is placed perpendicular to the line and the small angle subtended at the instrument is measured by a theodolite; $D = \dfrac{b}{2}\cot\dfrac{\theta}{2}$.
8. **Electronic distance measurement (EDM) and total station:** distance from the time or phase of electromagnetic waves. Very accurate and fast.

Additional methods: GNSS/GPS positioning, photogrammetry (from photographs) and LiDAR/laser scanning.

## Check yourself

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

1. What accuracy does pacing give?
   A. About 1/100, rough, for reconnaissance
   B. 1/10000
   C. 1/1000000
   D. Millimetre
   Answer: A. Pacing is a rough method around 1/100. (Key point: Pacing)

2. How does a measuring wheel (perambulator) get distance?
   A. Number of steps
   B. Revolutions x circumference
   C. Phase of a wave
   D. Staff intercept
   Answer: B. It counts revolutions of a wheel of known circumference. (Key point: Odometer)

3. In the subtense bar method, what is measured with the theodolite?
   A. The small angle subtended by a bar of known length, D = (b/2) cot(theta/2)
   B. The staff intercept
   C. The wave phase
   D. The pull
   Answer: A. A bar of fixed length perpendicular to the line subtends angle theta, from which D is computed. (Key point: Subtense bar)

4. Tacheometry finds distance from
   A. Time of a pulse
   B. Staff intercept between stadia hairs and the vertical angle
   C. Revolutions
   D. Paces
   Answer: B. A theodolite reads the intercept on a staff between the stadia hairs. (Key point: Tacheometry)

## Related in Surveying I

- [Linear measurement methods; sag correction](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Amethods-of-linear-measurement-sag) — Surveying I, chapter 2
- [Corrections in linear measurement](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Acorrections-linear-measurement) — Surveying I, chapter 2, asked 4×
- [Principle applied in two-way linear measurement](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Atwo-way-linear-measurement-principle) — Surveying I, chapter 1
- [Field sketch and mapping by linear measurement](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Achain-field-sketch-mapping) — Surveying I, chapter 3

## Related in other subjects

- [Stream flow from 0.2d and 0.8d measurements](https://www.bctengineer.com/question.md?key=semester_6%2Fhydro_power%3Astream-flow-measurement-data) — Hydro Power, chapter 2
- [Angular vs linear precision in traversing](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Atraverse-angular-linear-precision-relation) — Surveying II, chapter 1, asked 2×
- [Microwave vs low frequency measurement; static calorimeter](https://www.bctengineer.com/question.md?key=semester_7%2Frf_and_microwave_engineering%3Ameasurement-differences-static-calorimeter) — RF and Microwave Engineering, chapter 8
- [Omitted measurement cases, traverse plotting](https://www.bctengineer.com/question.md?key=semester_4%2Fsurveying_ii%3Aomitted-measurement-cases-plotting) — Surveying II, chapter 1