PHOTOGRAMMETRY

BEG231GE

Year: II Semester: III

Lectures: 45 Hours
Exercise: 15 Hours
Semester: III
Credit hrs.: 3
Full Marks: 100

Course Objective:

To provide general and theoretical knowledge on photogrammetry including:

• Aerial camera, aerial photographic mission, stereoscopic vision, parallax observation, etc.
• Aerial triangulation, stereo plotting instrument, photo interpretation, rectification, etc.

Course Details

1. Introduction and Definition (3 hrs.)

• Introduction
• Brief history
• Aerial and terrestrial photograph
• Basic principle of photogrammetry
• Definitions of terms used in photogrammetry:
  • Fiducial marks, principal point, principal distance, focal length, camera axis, picture plane, fiducial axis, iso-center, forward and side overlap, ground nadir, photo nadir, swing, drift, crab, sortie, flying height, flight line, exposure station
• Scope and application of photogrammetry

2. Aerial Camera (2 hrs.)

• Introduction
• Parts of aerial camera
• Types of camera
• Characteristics of aerial camera

3. Aerial Photography (9 hrs.)

• Photograph
• Aerial photograph
• Types of aerial photography: criteria for classifying aerial photography
  • Narrow angle, wide angle, super wide angle photography
  • Vertical, tilted, and oblique photographs
• Scale of aerial photography
• Format of the aerial photograph
• Scale of vertical photograph over a variable terrain
• Flight planning:
  • Effective coverage of the photography
  • Interval between exposures
  • Determination of number of photographs required to cover a given area
  • Flight plan, photo index
• Aerial photo processing
• Relief displacement
• Relief displacement on a vertical photo
• Tilt displacement
• Scale of tilted photograph
• Oblique photography

4. Binocular Vision (5 hrs.)

• Human eye and its characteristics
• Binocular vision from aerial photographs
• Stereoscopy, stereoscopic vision, stereoscope, stereoscopic fusion, pocket stereoscope, height measurement using parallax bar
• Pseudoscopic vision
• Anaglyph system
• Parallax
• Parallax in aerial stereoscopic views

5. Photo Interpretation (3 hrs.)

• Introduction
• Steps in photo interpretation
• Elements of photo interpretation

6. Rectification (5 hrs.)

• Introduction
• Conventional rectification
• Condition for rectification
• Differential rectification
• Ortho photo
• Photo mosaics:
  • Uses of photo mosaics
  • Mosaics category
  • Kinds of mosaics
  • Materials for preparing mosaics
  • Operations for controlled mosaics
• Photo rectification and enlargement

7. Photo Control and Aerial Triangulation (9 hrs.)

• Introduction to photo control
• Selection of photo control points
• Pre-marking and post-marking
• Properties of ideal GCP
• Point transfer
• Introduction to aerial triangulation
• Phases of aerial triangulation
• Methods of aerial triangulation adjustment

8. Analogue Photogrammetry (9 hrs.)

• Introduction to analogue plotters
• Types of stereo plotters
• General components of stereo plotter
• Principles of stereo plotters
• Mechanical projection stereo plotter
• Orientations: Inner, Relative, Absolute orientation
• Data acquisition

Exercise:

• Tie points selection, transfer, and overlap analysis
• Air flight planning for different scales
• Feature interpretation and feature extraction on transparent sheets
• Stereo pair and stereo viewing

Recommended Reading and Reference Books

1. Elements of Photogrammetry, Paul R. Wolf
2. Surveying, Vol. I – III, Dr. B. C. Punmia, A K Jain, and AK Jain, Laxmi Publishers (P) Ltd, New Delhi, India, Latest edition
3. Manual of Photogrammetry, R.N. Cornel, vol. 1-2, American Society of Photogrammetry and Remote Sensing
4. Mapping from Aerial Photographs (1985), C D Burnside, Colinas, London
5. Physical Aspect of Aerial Photography, G G Brook
6. Lecturer Notes

Final Examination Scheme

Model Questions:

Very Short Questions: [4*2=8]

1. Define photogrammetry.
2. Write formula to calculate scale of aerial photograph.
3. Write down the orientation steps in analogue stereo plotter.
4. Define pre-marking.

Short Questions: [8*4=32]

1. Describe iso-centre, ground, and photo nadir with diagram.
2. Draw and label the schematic diagram of aerial camera.
3. What are the things to consider during flight planning?
4. Explain the working principle of parallax bar with diagram.
5. Describe the element of photo interpretation.
6. Often equivalent photograph is enlarged during rectification. Describe the purpose of enlargement with diagram.
7. Describe the point transfer procedure during the preparation work in aerial triangulation.
8. Explain the general components of stereo plotter.

Long Questions: [2*10=20]

1. Derive an expression for relief displacement on a vertical photograph with diagram.
2. Describe the working procedure of mechanical projection stereo plotter.
   Or,
   Explain the preparation work in aerial triangulation.