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# What is Photogrammetry?

Photogrammetry is a technique used in surveying to measure the three dimensional coordinates with the help of photography. It is used for the purpose of measurements.

Fundamental Principle
Triangulation is the fundamental principle used by photogrammetry. In this technique, we take photographs from atleast two different locations. The purpose of taking pictures from more than 2 points is to create what engineers call “lines of sight.” Once these lines of sight are prepared, we join them to locate a point where they meet and thus calculate the coordinates of the desired point.

Scale formulas
Photo scale=ab/AB=f/(H-h1)
where f =focal length of lens, in (m)
H =flying height of airplane above datum (usually mean sea level), ft (m)
h1 =elevation of point, line, or area with respect to datum, ft (m)

### Kanwarjot Singh

Kanwarjot Singh is the founder of Civil Engineering Portal, a leading civil engineering website which has been awarded as the best online publication by CIDC. He did his BE civil from Thapar University, Patiala and has been working on this website with his team of Civil Engineers.

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## 6 comments on "What is Photogrammetry?"

nevin says:

thanx

PAVITHRA says:

Will this kind of survey is useful as i know this is not used by many.

sivakumar kakarla says:

We need detailed information about Photogrammetry.

Sivakumar Kakarla

Devjyoti says:

what is the basic principle of photogrammetry?
tell me how it is use with detail mathematical expression.

sayeed says:

how to find the complete notes of survey

VInod says:

Photogrammetry is the art and Science of without toching unkown area information finding with respective scale. But no professional vaules in India. Seeking to below Educational qualification persons also doing this technology and Campanies also paying very less salary. so Plz fullfill this. thankings to all Photogrammetry professionals.