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# Basic Concepts of Surveying | Part 1 | Introduction to Surveying | Explanatory Video | Surveying and Geomatics | By Ashutosh Nautiyal

Surveying Surveying is defined as the art and science of obtaining quantified and qualified measurements, the interpretation of these measurements and a meaningful presentation of result. Surveying is the collection of data or information. We are concerned with the surveying of geoinformation: For engineering projects For geographical mapping In surveying, there is a need for a reference system for fixing relative positions of points.

## Surveying

• Surveying is defined as the art and science of obtaining quantified and qualified measurements, the interpretation of these measurements and a meaningful presentation of result.

• Surveying is the collection of data or information.

• We are concerned with the surveying of geoinformation:

For engineering projects

For geographical mapping

• In surveying, there is a need for a reference system for fixing relative positions of points.

 Basic Concepts of Surveying (Part 1)

## Examples where Surveying is needed:

### Construction of a building

#### It includes:-

• Site selection

• Knowledge of topography (Map)

• Planning building on it

• Transfer building onto the site

### Town planning

#### It includes:-

• Site selection

• Knowledge of topography (Map)

• Planning town on it

• Transfer the town onto the ground

## Surveying: Two categories

### Surveying

Bringing the ground/terrain in laboratory/office for working upon it.

### Laying out

Taking the work onto the ground as per design specifications.

## Reference System for measuring Geoinformation of the Earth Surface

• X-Y plane (it can be used only for a mathematical surface).

• Geoid (everywhere in this surface, the potential is the same).

• MSL or Mean Sea Level (it is a geoid which is the average surface of the sea and it is measured over a period of 19 years).

• Ellipsoid

## There are two types of Surveying:

### Plane Surveying

• The surveying in which the earth's surface is considered to be flat.

• For a 20 km distance in the x-direction, the difference in distances between the arc and the corresponding chord will only be 10 mm.

• For a 20 km distance in the z-direction (or the geoidal height), the difference in distances between the arc and the corresponding chord will be 16 m which is a significant value.

• Plane surveying can be done for making a planimetric map which is only plotting X and Y (not Z or geoidal height).

• These surveys deal with areas of limited extent (areas less than 200 km2).

• For engineering projects like bridges, factories, dams, canals, railways, highways, etc. plane surveying is done.

### Geodetic Surveying

• The surveying in which the earth's curvature is considered.

• A higher degree of precision is exercised in linear and angular measurements in geodetic surveying.

• These surveys extend over large areas (such as a State or a Country).

*Self Typed
*Source- Internet, Books, Self-Analysis

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