RBSE 11th Geography Practical Book Solutions Chapter 6 Introduction To Aerial Photographs

Rajasthan Board RBSE Solutions for Class 11 Geography Practical Book Chapter 6 Introduction To Aerial Photographs

RBSE 11th Geography Practical Book Solutions Chapter 6 Introduction To Aerial Photographs

RBSE Class 11 Geography Introduction To Aerial Photographs Textbook Questions and Answers

Multiple Choice Questions

1. Choose the right answer out of the four alternatives given :
(i) In which of the following aerial photographs the horizon appears?
(a) Vertical 
(b) Near-vertical
(c) Low-oblique 
(d) High-oblique
Answer: 
(d) High-oblique.

(ii) In Which of the following aerial photographs the Nadir and the principle points coincide?
(a) Vertical
(b) Near-vertical
(c) Low-oblique 
(d) High-oblique
Answer: 
(a) Vertical.

(iii) Which type of the following projections is used in aerial photographs?
(a) Parallel 
(b) Orthogonal
(c) Central 
(d) None of the above.
Answer: 
(c) Central.

Short Answer Type Questions

1. State any three advantages that an aerial photograph offers offer over ground based observations.
Answer: 
The advantages are:

• Improved vantage point
• Time freezing ability
• Broaded sensitivity
• Three dimensional perspective

 2. How is an aerial photograph taken?
Answer: 
The aerial photograph is taken from an aircraft or a helicopter using a precision camera.

3. Present a concise account of aerial photography in India?
Answer: 
Aerial photographs were started in 1920 when large scale aerial photograph of Agra City was taken. Air survey party of survey of India took up erial survey at Irawadi Delta forests which are completed in 1923¬24. Today aerial photographs in India are carried out for the entire region unair the overall supervision of the Directorate of Air Survey, New Delhi. Three flying agencies are Indian Air Force, Air Survey Company, Kolkata and National Remote Sensing Agency, Hyderabad have been afficially authorised to take aerial photographs. 

4. Answer the following questions in about 125 words:
(i) What are the two major uses of an aerial photograph? Elaborate.
Answer: 
The uses of an aerial photographs are:

• Photogrammetry: The technique of obtaining information from photographs is called photogrammetry of making reliable measurements from aerial photographs.
• Image Interpretation: It is an art of identifying images of objects and judging their relative significance.

(ii) What are the different methods of scale determination?
Answer: 
There are three different methods of scale determination these are: 

(Introduction to Aerial Photographs } 

(1) By establishing relationship between photo distance and ground distance: In this method if additional information like ground distance of two identifiable points in an aerial photograph is available it is simple to work out the scale of vertical photograph.

(2) By establishing relationship between photo distance and map.

(3) By establishing relationship between focal length and flying height of the Aircraft. 

RBSE Class 11 Geography Introduction To Aerial Photographs Important Questions and Answers

Short Answer Type Questions

Question 1. 
What is meant by ‘Photogrammetry’?
What is Aerial Photography? 
Answer: 
Aerial photography means sensing the images of the earth's surface through cameras fitted in an airplane. Some photographic images record the original landscape as observed at a particular point of time, and these images help in preparing the map of the area. This technique of obtaining information from photographs is called photogrammetry. Aerial photography is the science of making photographs from the air, for studying the surface of the earth. The main uses of aerial photography are for pictorial representations e.g., photo mosaic, photo¬interpretations and photogrammetric survey.
 
Question 2. 
Describe aerial photography in India.
Answer: 
Aerial photography in India is controlled and co-ordinated by the Survey of India. It is carried out by hiring flying agencies. Once the scale and type of photography are indicated, the Survey of India designs the photographic specifications and places the order for photography on one of the three flying agencies, viz. The Indian Air Force, M/s Air Survey Company (Pvt.) Ltd., Dum Dum and National Remote Sensing Agency, Hyderabad. The flying agency is responsible for executing the photography and supply of photographic prints and enlargements.

Question 3. 
Describe the different types of air photography.
Answer: 
Types of Air Photographs
According to the position of the axis of the camera, the air photos may be grouped as

• Vertical 
• Horizontal
• Oblique 
• Convergent, and
• Trimetrogen.

(i) The axis of the camera is vertically adjusted to take the photographs. Inspite of all possible precautions, it is difficult to get a complete vertical aerial photograph. That is why photographs having an inclination of axis upto 2-degrees, are grouped in the category of vertical photographs. The areas covered through vertical air photos are often square in shape at the uniform plane.

(ii) The horizontal air photos are also called Terrestrial air photos. In the production of such air photos, the axis of the camera is horizontally adjusted.
 
(iii) In the oblique air photos, the adjustment of the axis of the camera ranges from vertical to angular position. The areas covered by oblique air photos assume the shape of a trapezium.

(iv) The convergent air photos are also oblique, but an area is simultaneously photographed by two cameras.

(v) In trimetrogen air photos, three cameras are used simultaneously amongst which the central camera is vertical, and the other two are adjusted to oblique positions. In addition, on the basis of the films used in the cameras, the air photographs are classified as Black and White, Infrared and Coloured.