introduction to photogrammetry

1. Presented to; Engr. Azmat ali shah
Presented by Hayat khan
ID; 11664

5. PHOTOGRAMMETRY
 It is a branch of surveying in which
photographs are taken from an aircraft
(or from the ground in some cases) to
indirectly measure objects on the ground
to produce point coordinates or maps.
 The term “photogrammetry” is
composed of the words “photo” and
“meter” meaning measurements from
photographs.

7. History
 The first use of photogrammetry was by
Arago, a French geodesist, in 1840.
 The first aerial photogrammetry was by
the French in 1849 using kites and
balloons.
 Laussedat (French) – father of
photogrammetry.

8. History
 Airplanes brought great change to
photogrammetry.
 1st used in 1913.
 Aerial photographs were taken in WW1
and WW2 for preparing maps.
 Due to improvement in computer digital
photogrammetry is gaining more and
more importance.

9. Types of photogrammetry
Arial.
Terrestrial.

10. Terrestrial photoghraphs
 Taken with a phototheodolite from the
camera stations on the ground.
 The phototheodolite set at elevated
ground.

12. Arial photoghraphs
 Taken from the camera stations in the
air with the axis of camera vertical or
nearly vertical.
 Photographs are overlap from 55 to
65%.

14. Advantages of photogrammetry.
 cost effected for large areas.
 photographs takes of dangerous area
than to place surveyors in harms way.
 • Photogrammetry provides the ability to
map areas inaccessible to field crews.
 • Photogrammetry creates a
photographic record of the project site.

15. Advantages of photogrammetry
 Very quick and accurate method.
 It is provide the mean to develop a
contour map.

16. Disadvantages of
photogrammetry
 Required fair and clean weather
condition.
 Very expensive for surveying of small
area.
 High qualified and experienced staff
required.

17. Principle of
photogrammetry.
 Similar to plane table survey.
 The difference is in plane survey most
the work done at field but in
photogrammetry most of work is done at
office.
 Suitable for engineering survey for
construction of some project when high
accuracy is required.

18. Principle of
photogrammetry.
 Unsuitable for dense forests, flat area
with sand due to difficulty to identity
point upon the pair of photographs.
 Suitable for mountainous and hilly area
without dense forest.

19. THANK YOU