---
title: "Objectives of surveying; plane vs geodetic"
subject: "Surveying I"
chapter: 1
key: "semester_3/surveying_i:objectives-plane-geodetic"
source: https://www.bctengineer.com/q/semester_3/surveying_i/objectives-plane-geodetic
site: BCT Engineering
---

# Objectives of surveying; plane vs geodetic

Surveying I · Chapter 1: Introduction

- Asked in: 2073 Shrawan, 4 marks
- Video: [Primary Divisions of Surveying [Plane and Geodetic] | Explained Objective Questions of Surveying](https://www.youtube.com/watch?v=2DmyJDd4rLU) — Simplified Learning Civil Engineering
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_3/surveying_i/objectives-plane-geodetic
- Whole chapter: https://www.bctengineer.com/md/semester_3/surveying_i/chapter-1

## Question

Explain about the objectives of surveying. Differentiate between plane and geodetic surveying.

## Short answer

Surveying aims to prepare plans, gather design data, set out works, compute areas/volumes, fix boundaries, and establish control. For the difference, plane surveying neglects earth's curvature for areas ≤250 km²; geodetic surveying considers curvature for larger areas with high precision.

## Answer

#### Objectives of surveying
Surveying is the measurement of distances, angles and elevations to fix the relative positions of points. Its main objectives are:

1. To prepare plans, maps and sections (topographic, cadastral, engineering) of the ground.
2. To collect data needed for the planning and design of engineering projects such as roads, railways, canals, bridges, dams and buildings.
3. To set out (mark on the ground) the designed work in the correct position and level.
4. To determine areas, volumes and the quantities of earthwork.
5. To fix property boundaries and to settle land disputes.
6. To establish control points for further surveys.
7. To check the work during and after construction (deformation and progress monitoring).

#### Plane and geodetic surveying

| Basis | Plane surveying | Geodetic surveying |
|---|---|---|
| Curvature | Neglected | Considered |
| Area | Up to about 250 km$^2$ | Above 250 km$^2$ |
| Level line | Straight line | Curved line |
| Accuracy | Ordinary | High |
| Triangle | Plane; sum $= 180^\circ$ | Spherical; sum $> 180^\circ$ |
| Instruments | Chain, compass, theodolite | Precise theodolite, EDM, GNSS |
| Purpose | Local works | Control for large areas and countries |

## Check yourself

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

1. Setting out in surveying means
   A. measuring areas of a plot
   B. drawing a map from field notes
   C. checking the instrument error
   D. marking the designed work on the ground in correct position and level
   Answer: D. One objective is to mark the designed work on the ground. (Key point: Setting out)

2. Which is an objective of surveying?
   A. Determining areas, volumes and earthwork quantities
   B. Designing the reinforcement of beams
   C. Mixing concrete
   D. Calculating wages
   Answer: A. Surveys give data for areas, volumes and earthwork quantities. (Key point: Objective)

3. Which pair is correct?
   A. Plane: level line curved; Geodetic: straight
   B. Plane: level line straight, sum 180°; Geodetic: level line curved, sum > 180°
   C. Plane: sum > 180°; Geodetic: sum = 180°
   D. Both have the same level line and area
   Answer: B. Plane surveying treats the level line as straight; geodetic treats it as curved. (Key point: Plane vs geodetic)

## Related in Surveying I

- [Plane versus geodetic surveying](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Aplane-vs-geodetic-surveying) — Surveying I, chapter 1, asked 5×
- [Plane and geodetic surveying; principles](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Aplane-geodetic-and-principles) — Surveying I, chapter 1, asked 7×
- [Classification of surveying](https://www.bctengineer.com/question.md?key=semester_3%2Fsurveying_i%3Aclassification-of-surveying) — Surveying I, chapter 1, asked 4×