HANSABA COLLEGE OF ENGINEERING & TECHNOLOGY, SIDHPUR (098)

DEPARTMENT OF CIVIL ENGINEERING (06)

ELEMENTS OF CIVIL ENGINEERING(2110004)

Guided by:Prof. Mehul Chaudhary

Head of Dept.:Prof. Rahul Rathod

Presented by:1) Patel Suhag B. (130980119075)2) Patel Tarang (130980119076)3) Patel Utsav J. (130980119077)4) Prajapati Ashvin M.

(130980119079)

Introduction TO ANGULAR MEASUREMENTS

Introduction

The Angular Measurements are taken using an instrument known as compass.

Compass Surveying may be defined as the branch of surveying in which the position of an object is determined by Angular Measurements.

Linear Measurements in a traverse are measured using a chain or a tape.

Traverse

Traverse is a geometric figure consisting of series of connected lines.

It has two types: (1) Open traverse

(2) Closed traverse

Open traverse When the starting point does not coincide

with the end point, as shown in figure below, the traverse is called Open traverse or Unclosed traverse.

AB

C

D E

Closed Traverse When the starting point coincides with the

end point as shown in figure, the traverse is called Closed Traverse.

AB

C

D E

Methods of traversing

I. Chain traversing or Chain angle method:- In this method the entire work is done by chain or tape. Angles are fixed by measuring tie lines. Such angles are known as chain angles.

II. Loose or free needle method:- In this method, the angular measurement is taken using a compass or a theodolite. Bearing of each line of traverse is taken with reference to magnetic meridian.

III. Fast needle method:- In this method a theodolite is used to determine bearing of different lines of the traverse.

IV. Angular measurement method:- In this method, a theodolite is used to measure either included or deflection angles between successive lines of the traverse.

Instruments for measurements of angles

Following instruments are commonly used for measurement of angle:

1) Compass:

a) Prismatic compass

b) Surveyor’s compass

c) Trough compass

d) Tubular compass

2) Theodolite

3) Sextant

A compass essentially consists of:1) A magnetic needle

2) A graduated circle

3) A line of sight

Prismatic Compass

Surveyor’s Compass

Tubular Compass

Trough Compass

Theodolite Sextant

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