Types of Photogrammetry and Application of Photogrammetry

Introduction to Photogrammetry
The word photogrammetry is derived from three Greek words: Photos, Gramma and Metron. Photos mean ‘light’ Gramma means ‘something drawn or written’ and Metron means ‘to measure’. So Photogrammetry can be defined as a technique used in surveying to measure the three-dimensional coordinates with the help of photography (Photos). It is used for the purpose of measurements. 

This definition, over the years, has been enhanced to include interpretation as well as the measurement with photographs. 

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Definition of Photogrammetry

According to (American Society of Photogrammetry, Slama).

The art, science, and technology of obtaining reliable information about physical objects and the environment through the process of recording, measuring, and interpreting photographic images and patterns of recorded radiant electromagnetic energy and phenomenon.

Initially, photogrammetry was considered as the science of analyzing only photographs. But now it also includes analysis of other records as well, such as radiated acoustical energy patterns and magnetic phenomenon.

Definition of photogrammetry includes two areas: 

(1) Metric:

It involves making precise measurements from photos and other information sources to determine, in general, relative location of points. Most common application: preparation of planimetric and topographic maps.

(2) Interpretative:

It involves recognition and identification of objects and judging their significance through careful and systematic analysis. It includes photographic interpretation which is the study of photographic images. It also includes interpretation of images acquired in Remote Sensing using photographic images, MSS, Infrared, TIR, SLAR etc.

Also Read: GIS, Definition of Geographical Information System

Types of Photogrammetry:

Aerial Photogrammetry 

In Aerial Photogrammetry Photographs of an area are taken by a precision photogrammetric camera mounted in an aircraft flying over an area pointing vertically downward towards ground. 

Terrestrial Photogrammetry 

In case of Terrestrial Photogrammetry Photographs of an area are taken from fixed and usually known position or near the ground and with the camera axis horizontal or nearly horizontal.

Applications of photogrammetry

Photogrammetry has been used in several areas. The following description give an overview of various applications areas of photogrammetry

  

(1) Geology: 

The use of photogrammetry in geology field is under Structural geology. For the investigation of water resources, analysis of thermal patterns on the earth's surface and also geomorphological studies photogrammetry is widely used. 

(2) Forestry

With the help of photogrammetry, the work like timber inventories, cover maps, acreage studies for forestry is made simpler. 

(3) Agriculture 

To check the Soil type, soil conservation, crop planting, crop disease, crop-acreage on a particular land, photographs are used and hence to get information of the land area of agriculture, photogrammetry is used. 

(4) Design and construction 

Data needed for site and route studies specifically for alternate schemes for photogrammetry. Used in design and construction of dams, bridges, transmission lines.

(5) Planning of cities and highways 

To establish new highway locations, detailed design of construction contracts, planning of civic improvements, highway alignments photogrammetry is very helpful.

(6) Cadastre 

Cadastral problems such as determination of landlines for assessment of taxes. Large-scale cadastral maps are prepared for reapportionment of land. 

(7) Exploration 

To identify and zero down to areas for various exploratory jobs such as oil or mineral exploration.

(8) Military intelligence 

Reconnaissance for deployment of forces, planning maneuvers, assessing effects of the operation, initiating problems related to topography, terrain conditions or works. 

(9) Medicine and surgery 

Stereoscopic measurements on the human body, X-ray photogrammetry in the location of foreign material in body and location and examinations of fractures and grooves, biostereometrics.

(10) Miscellaneous 

Crime detection, traffic studies, oceanography, meteorological observation, Architectural and archaeological surveys, contouring beef cattle for animal husbandry etc. 

Source: http://aerialsurveys.ces.eu.com

Conclusion

So, in this short article about Photogrammetry, you have got a basic idea about it. in further articles, we will discuss in depth knowledge about photogrammetry.

If you have any queries feel free to ask in the comment box below.