This document discusses photogrammetry and its applications. It describes the different types of aerial photographs based on lens systems and film properties. It then lists several applications of aerial photogrammetry including forestry, geology, agriculture, urban planning, and military intelligence. Finally, it explains some key principles of photogrammetry including central projection, orthogonal projection, stereo pairs, principal points, and fiducial marks.

1. Topics
Photogrammetry : Part 2
• Geometry of Aerial photographs – Tilt,
Swing,
• Photo nadir, Principle points,
• Principal distance, flying height, air base,
overlaps, side laps,
Prasenjit Bhowmick

2. Elements of Photogrammetry
Types of Aerial Photographs (Conti.)
2. According to Lens system
• Single lens photography
• Three lens photography
• Four and Nine lens photography
3. According Film properties
• Black and White
• Colour
• Infra-red
• Thermal infra-red
Photogrammetry

3. Photogrammetry
Aerial photogrammetry is mainly used to produce topographical or
thematic maps and digital terrain models
 Forestry : Timber inventory, acreage studies, fire control
 Geology : Investigation of Water resources, Mineral, Oil etc.
 Agriculture : Study soil types, soil conservation, crop planting, crop
diseases
 Design and Construction : Dams, bridges, transmission lines
 Urban Planning : Sewerage planning, highway planning
Application of Aerial Photographs

4.  Cadastral : Landlines for real estate tax studies
 Environmental Studies : Impact analysis
 Military Intelligence : Surveillance, deployment of
forces, planning of maneuvers
 Others : Crime detection, traffic studies, oceanography,
meteorological observations, archeological surveys, etc.
Photogrammetry
Application of Aerial Photographs

5. The Principle of Photogrammetry
Photogrammetry
1. Central Projection
Every point of the ground is projected on to the plane
after passing through one point

6. The Principle of Photogrammetry
Photogrammetry
1. Central Projection
2. Orthogonal Projection

7. TREE
ROCK
LENS
FILMSUN
Photogrammetry

8. PHOTO PROJECTED ON FLAT PLANE
TREE
ROCK
LENS
FILMSUN
LIGHT RAYS OF A PHOTO UBABLE TO INTERSECT A
FLAT PLANE IN THE CORRECT POSITIONS.
DISTORTION IS RELATED TO DIFFERENCES IN
GROUND ELEVATION AND POSITION WITHIN THE
PHOTO.
Photogrammetry

9. INTERSECTING LIGHT RAYS FROM TWO PHOTOS
TREE
ROCK
LENS
FILMSUN
RAYS FROM TWO PHOTOS INTERSECT AT
THE CORRECT HORIZONTAL AND VERTICAL
POSITIONS OF THE OBJECTS.
Photogrammetry

11. Photogrammetry
Pattern of Aerial Photography

12. Photogrammetry
Pattern of Aerial Photography

13. Photogrammetry

14. Elements of Photogrammetry
Photogrammetry

15. Photogrammetry
StereoPair

16. Photogrammetry
StereoPair

17. The Principle of Photogrammetry
Photogrammetry

18. Photogrammetry

19. The Principle of Photogrammetry
Photogrammetry
1. Principal Point : point perpendicular projected through
the center of the lens.
2. Nadir : Point vertically beneath the camera center at
the time of exposure.
3. Isocenter : Point of photo falls on a line half- way
between the principal point and the Nadir point.
For true vertical aerial photograph these three points are a
single point.
All air photos have some degree of tip or tilt.

20. Photogrammetry
Inclined Photograph
The Principle of Photogrammetry
4. Conjugate Principal Point : The principal point of an
aerial photo.
5. Fiducial marks : index marks rigidly connected with
the camera lens.

21. Elements of Photogrammetry
Photogrammetry
Principal
Point
Fiducial
Mark

22. Fiducial Mark
Principal Point Conjugate Principal Point
Photogrammetry