There are two forms of the compass in common use: 1. The Prismatic Compass 2. The Surveyor’s Compass. A compass is a small instrument which consists essentially of a magnetic needle, a graduated circle and a line of sight. When the line of sight is directed towards a line, the magnetic needle points towards magnetic […]

# Tag Archives | Surveying

## Methods Adopted to Find Areas from Plotted Plans | Land Surveying |Surveying

The following two methods are generally adopted to find the areas from the previously plotted plans. The methods are: 1. Graphical Method. 2. Instrumental Method. 1. Graphical Method: In this method, the required data is obtained from measurements of the plan. The area may be found: (i) By the help of some geometrical figures or […]

## Using the Compass During Survey: 8 Precautions | Compass Surveying | Surveying

After reading this article you will learn about eight main precautions that should be taken while using a compass. Also learn about the sources of error in compass work. 1. The glass cover of the compass box gets charged with electricity when dusted off with a handkerchief or by the influence of electric charge in […]

## Error Occurs in Compass Surveying of Land | Compass Surveying| Surveying

The compass ring is graduated to half a degree but the readings can be well estimated to 15 minutes, which means that the error of reading should not exceed 7½ minutes. But due to magnetic changes and variation of declination etc., the readings can seldom be relied upon to less than 10 minutes, therefore, the […]

## Bearing of a Line and Its Designation | Compass Surveying | Surveying

After reading this article you will learn about the meaning of bearing of a line and its designation with examples. Bearing of a line is the horizontal angle which a line makes with some reference direction also known as meridian. The reference direction may be any of the following: 1. A true meridian 2. A […]

## Calculation of Angles from Bearings | Compass Surveying | Surveying

Bearings of lines may be calculated if bearing of one of the lines and the included angles measured clockwise between the various lines are given. Bearing of a line = given bearing + included angle. Note: In a closed traverse, where local attraction is not suspected i.e. difference between F.B. and B.B of all lines […]

## Field-Work in Compass Surveying | Compass Surveying |Surveying

After reading this article you will learn about the field-work in compass surveying. 1. Field-Party: It will consist of four persons: (i) Surveyor for taking bearings of the lines, recording field-notes and imparting instructions to other party members. (ii) Two chainmen for chaining the survey lines. (iii) One flagman, cum pegman to fix stations, pegs […]

## Local Attraction (With Remedies) | Compass Surveying | Surveying

This article provides a note on local attraction along with its remedies and examples. The magnetic needle is disturbed from its normal position if it is under the influence of external attractive forces called the sources of local attraction. Such a disturbing influence is known as local attraction. The term is also used to denote […]

## Problems in Ranging and Chaining of a Line | Chain Surveying | Surveying

This article throws light upon the six major problems in ranging and chaining of a line. Problem # 1. To erect, with a tape, a perpendicular to a chain line from a point on it: It can be done by forming a right angled triangle by taking three sides of a triangle in the proportion […]

## Magnetic Declination: Meaning and Variation | Compass Surveying |Surveying

After reading this article you will learn about the meaning and variation of magnetic declination, with some examples. Meaning of Magnetic Declination: Except in few places, the magnetic meridian at a place does not coincide with the true meridian at that place. The horizontal angle which the magnetic mariotion makes with the true meridian is […]