NCERT Class 11 Geography Chapter 30 Introduction to Remote Sensing

NCERT Class 11 Geography Chapter 30 Introduction to Remote Sensing Solutions to each chapter is provided in the list so that you can easily browse through different chapters NCERT Class 11 Geography and select need one. NCERT Class 11 Geography Question Answers Download PDF. NCERT Geography Class 11 Solutions.

NCERT Class 11 Geography Chapter 30 Introduction to Remote Sensing

Also, you can read the NCERT book online in these sections Solutions by Expert Teachers as per Central Board of Secondary Education (CBSE) Book guidelines. CBSE Class 11 Geography Solutions are part of All Subject Solutions. Here we have given NCERT Class 11 Geography Part I: Fundamentals of Physical Geography, Part II: Indian: Physical Environment, Part III: Practical Work in Geography. NCERT Class 11 Geography Notes, NCERT Class 11 Geography Textbook Solutions for All Chapters, You can practice these here.

Introduction to Remote Sensing

Chapter: 30

GEOGRAPY [ PART – III ]

VERY SHORT ANSWER TYPE QUESTIONS

Q.1. What is remote sensing?

Ans. Remote sensing is the science of gathering information about objects from a distance without coming into physical contact with them. It thus include data gathered through photographs taken from air planes and satellites.

Q.2. What is meant by photogrammetry?

Ans. The technique of obtaining information from photographs is called photogrammetry.

Q.3. What is sensor?

Ans. Sensor is another parameter to determine the types of remote sensing. According to the sensor remote sensing is of two types.

(a) Photographic.

(b) Non-photographic.

Q.4. Which equipments are used in interpreting air photos?

Ans. In air photo interpretation of maps, stereoscopes and sketch masters are mostly used. Stereoscope comprises two lenses placed at the same plane termed as pocket stereoscope and mirror stereoscope.

Q.5. What are the major types of air photographs?

Ans. Air photographs can be grouped in five types.

1. Vertical.

2. Horizontal.

3. Oblique.

4. Convergent.

5. Trimetrogen.

Q.6. What is active remote sensing?

Ans. Active remote sensing is the science of recording the information energy activated by man like flash guns and microwave radar.

SHORT ANSWER TYPE QUESTIONS

Q.1. What are satellite imageries?

Ans. Satellite imageries are the practical value to geographers because they provide synoptic coverage of large areas and permit a more accurate regional mapping of natural resources. It is obtained through the techniques of remote sensing.

Q.2. Name the eight elements mostly used for image interpretation.

Ans. The following eight elements are mostly used for image interpretation are:

1. Size.

2. shape.

3. shadow.

4. tone.

5. colour.

6. texture.

7. pattern.

8. associated relationship.

Q.3. How does one distinguish between tropical rainforests and tropical grasslands on satellites images?

Ans. Tropical rainforests have a near continuous canopy with few clearings. Tall trees 75 to 80 metres can be easily recognised under stereoscope by their dome like tops. They appear as unbroken sheet of dark tone on the photograph. Tropical grassland (Savanna) is marked by scattered groves. Grass appears in light grey tones and trees in darker tones.

LONG ANSWER TYPE QUESTIONS

Q.1. Discuss the advantages of remote sensing.

Ans. The advantages of remote sensing are follows:

1. It gives a synoptic view of region rather than a district or block.

2. It provides a reliable and real or near real time base line information.

3. It is relatively fast and economical as compared to ground survey.

4. It provides analogue and digital data for visual and digital interpretation respectively.

5. It provides repetitive coverage of the some area which is useful for change monitoring.

6. It is unaffected by bad weather or difficult ground conditions.

Q.2. Distinguish between air photos and satellite images. Explain the main conceptual terms relevant to each.

Ans. Air Photos: Aerial photography means sensing the images of the earth’s surface through cameras fitted in an aeroplane. According to the position of the axis of camera, the air photos may be grouped as vertical, horizontal, oblique, convergent and trimetrogen.

Satellite Images: Satellite imagery contrary uses a different mechanism of generating ground images. A ground sense imaged by a sensor board. The features on the earth’s surface are captured in these imageries by detecting characteristics electromagnetic radiation that is reflectance any object of different wavelengths follows a pattern which is characteristics of that object.

Q.3. Describe the development of satellite remote sensing in India.

Ans. Remote sensing in India has grown very fast since 1980s. The remote sensing satellites IRS-IA was launched in 1988 and IB in 1991 alongwith setting up of information system like National Natural Research Management System, National Resources Information System and other remote sensing services, the country provided the desired push for growth. There are 350 national/regional level remote sensing. Indigenously built IRS-IC satellite was launched on 28 December 1995. IRS-ID, IRS-P3 and IRS-P4 are the new varieties. These are the developments in remote sensing organisation. Browse data and self scanning are being generated for users. The IRS-IC and IRS-ID mark a major milestone in remote sensing programme by NNRMS. The Panchromatic Camera (PAN) provides very high spatial resolution data of 5.8 m and a grand swath of 70 km. All three cameras are operating in real time over Indian ground stations.

Q.4. How are physical and cultural features on satellite imageries identified and interpreted? Explain giving suitable examples.

Ans. The eight elements like size, shape, shadow, tone, colour, texture, pattern and relationship are used to identified the physical and cultural features.

Cultural features: These are easily recognisable features in an aerial photograph. Railway lines appear as thin and dark. Certain associated features like stations and sidings make their identification easier. Roads are noticiable through lighter tone. Bridges are recognised as they span water bodies. Urban features like residential buildings, offices etc. can be easily recognised.

Physical features: Tropical rainforests have a near continuous canopy with few clearings. They can be easily identified as the trees are tall to 75-80 m. They appear as un- broken sheet of dark tone. Grasslands are marked by groves. Grass appears in light grey tones in darker tones.

Q.5. Discuss the role and functions of the National Remote Sensing Agency.

Ans. The National Remote Sensing Agency, an autonomous organisation under the department of space, Government of India, established in 1974. Its functions are as under:

1. Remote sensing satellite data acquisition, storage processing and dissemination.

2. Application of remote sensing for mapping monitoring and management of natural resources.

3. Operational flight facilities to provide several remote sensing services.

4. Training to users.

5. Research and technology development.

Q.6. Describe in brief the Functioning of Pushbroom Scanner?

Ans. Pushbroom Scanners: The pushbroom scanners consist of a number of detectors which are equivalent to the number obtained by dividing the swath of the sensor by the size of the spatial resolution. For example, the swath of High Resolution Visible Radiometer -1 (HRVR-1) of the French remote sensing satellite SPOT is 60 km and the spatial resolution is 20 metres. If we divide 60 km × 1000 metres / 20 metres, we get a number of 3000 detectors that are deployed in SPOT HRV -1 sensor. In pushbroom scanner, all detector are linearly arrayed and each detector collects the energy reflected by the ground cell (pixel) dimensions of 20 metres at a nadir’s view.

Q.7. Describe the operation of a Whiskbroom Scanner with the help of a diagram? Explain how it is different from pushbroom scanner?

Ans. Whiskbroom Scanner and it operation: The whiskbroom scanner is made up of a rotating mirror and a single detector. The mirror is so oriented that when it completes a rotation, the detector sweeps across the field of view between 90° and 120° to obtain images in a large number of narrow spectral bands ranging from visible to middle infrared regions of the spectrum. The total extent of the oscillating sensor is known as the Total Field of View (TFOV) of the scanner. While scanning the entire field, the sensor’s optical head is always placed at a particular dimension called the Instantaneous Field of View (IFOV) figure depicts the scanning mechanism of whiskbroom scanner. The pushbroom scanner consist a large number of ditietois which are equalent to the number obtained by dividing the swatch of the season. Whiskbroom scanner is made up at relating mirror and single distietor.

Q.8. Identify and list the changes that can be observed in the vegetation of Himalayas.

Ans. The cousiferrous forests are disappeared and the diciduous forests have taken place of consiferrours forests.

Q.9. Why is remote sensing a better technique then other traditional methods.

Ans. The remote sensing is better technique other than traditional technique because this remote sensing is done by satellites which have capabilities of covering a large area.

Q.10. Differentiate between IRS and INSAT Series of Satellites.

Ans. The sensors recording the energy that they receive are placed in a near-polar sun synchronous orbit at an altitude of 700-900 km. These Satellites are known as remote sensing satellites (e.g. Indian RemoteSensing Series). As against these satellites, the weather monitoring and telecommunication satellites are placed in a Geostationary position (the satellite is always positioned over its orbit that synchronises with the direction of the rotation of the earth) and revolves around the earth (coinciding with the direction of the movement of the earth over its axis) at an altitude of nearly 36,000 km (e.g. INSAT series of satellites).