## Principles of Chain Surveying or Linear Surveying | Civil Engineering

#### Chain Surveying or Linear Surveying | Surveying and Levelling

It is the method of land surveying in which only linear measurements are made.

Chain surveying requires chain, tape and ranging rods.

Chain surveying is not suitable for large areas having many details.

(The term “details” means a natural or manmade features at or near the ground surface).

It consists of the following:

#### Hard details

Hard details include buildings, roads, walls etc.

#### Soft Details

Soft details include river, vegetation, trees etc.

Overhead details include power and telephone lines.

#### Underground details

Underground details include survey of water mains, sewer etc.

#### Principles of Chain Survey

A triangle is a simple figure which can be plotted from the lengths of three sides even if the angles are not known.

In chain survey, the area to be surveyed is divided into a framework consisting of triangles.

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## Height of Instrument Method | Surveying and Levelling

Height of the Instrument Method The following readings were observed with a levelling instrument, the instrument was shifted after 5th and 11th reading. 0.585, 1.010, 1.735, 3.295, 3.775(5th) 0.350, 1.300, 1.795, 2.575, 3.375 3.895 (11th), 1.735, 0.635, 1.605 Determine the RLs of various points if the reduced level (RL) of a point on which the … Read more Height of Instrument Method | Surveying and Levelling

## Conventional Signs or Symbols | Surveying and Levelling

#### Conventional Signs and Symbols used in Surveying

Here are a few important Conventional Signs and symbols useful in the field of Surveying:

1. Marsh or Swarm
2. House
3. Embankment
4. Cutting
5. Single Line Railway
6. Double Line Railway
7. Lake or Pond
9. Railway Bridge
11. River
12. Fence

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## Different Methods for the Calculation of Areas in Surveying

#### Different methods for the calculation of Areas in the field of Surveying

In this article, we will list out different methods to calculate the areas in Surveying and also study each of the method in depth… We will also explain each method with a suitable example for your better understanding…

#### Here are the five important rules (Methods) used for the calculation of areas in Surveying:

1. Midpoint ordinate rule
2. Average ordinate rule
3. Simpson’s rule
4. Trapezoidal rule
5. Graphical rule

We will now move on with our discussion on the first rule “Midpoint ordinate rule” with a suitable example.

#### Midpoint-ordinate rule

The rule states that if the sum of all the ordinates taken at midpoints of each division multiplied by the length of the base line having the ordinates (9 divided by number of equal parts).

In this, base line AB is divided into equal parts and the ordinates are measured in the midpoints of each division.

Area = ([O1 +O2 + O3 + …..+ On]*L)/n

L = length of baseline

n = number of equal parts, the baseline is divided

d = common distance between the ordinates

#### Example of the area calculation by midpoint ordinate rule

The following perpendicular offsets were taken at 10m interval from a survey line to an irregular boundary line. The ordinates are measured at midpoint of the division are 10, 13, 17, 16, 19, 21, 20 and 18m. Calculate the are enclosed by the midpoint ordinate rule.

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