Duties of a Surveyor in the field of Surveying | Civil Engineering

Role of a Surveyor | Surveying and Levelling

Surveying is a subject that is studied by Civil Engineers as well as Architects. Some Civil Engineers take up Surveying as their profession but otherwise, there are surveyors who have the expertise in the field of surveying.

They have certain important duties as a Surveyor to be carried out. In this article, we will briefly discuss their division of work and their duties towards the field of Surveying.

The work of a surveyor can be divided into four parts:

  1. Field work
  2. Computing
  3. Mapping
  4. Setting

Field work

Making and recording measurements in the field.

Computing

Making the necessary calculations to determine areas, location, volume etc.

Read moreDuties of a Surveyor in the field of Surveying | Civil Engineering

Tape Correction, Sag Correction and Pull Correction | Surveying and Levelling

Tape Correction, Sag Correction, Pull Correction and Temperature Correction

In this article, I will list out different formulas for the respective corrections…

Tape Correction

The following corrections are to be made for measurements taken with a tape because tape can never be practically used under specified standard conditions.

Correction for absolute length

Absolute length of tape is its actual length under specified condition

Ca = Lc/L

Where, Ca = correction to be applied to the tape in ‘m’

Lc = measured length in ‘m’

L = nominal length of tape in ‘m’

Correction for temperature

Length of tape is increased with the increase of temperature and decrease with decrease of temperature.

Ct = A (Tm – Ts)

Where,

A = coefficient of thermal expansion per one degree Kelvin

Tm = temperature during the measurement in Kelvin

Ts = temperature at which the tape standardised in Kelvin

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Errors in Chaining | Guide to Surveying and Levelling

Types of Errors occurring in Chain Surveying

There are two types of Errors that are commonly seen to occur in Chain Surveying. For students studying the concept of Chain Surveying, study of the occurrence of different types of Errors in Chain Surveying is important. In this article, we will briefly discuss different types of Errors in Chain Surveying and the situations in which they occur.

Types of Errors:

  1. Cumulative error
  2. Compensative error

Cumulative error

These errors always accumulate in one direction and are serious in nature. They affect the survey work considerably.

They make measurements too long or too short.

These errors are of two types and are known as systematic errors.

They are classified as follows:

  1. Positive error
  2. Negative error

Positive error

These errors make the measured length more than the actual length which results into wrong calculations by the Surveyor.

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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).

Midpoint ordinate rule | Method for calculating area in Surveying
Midpoint ordinate rule | Method for calculating area in Surveying

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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