Remote Sensing

I. Choose the correct answer:

1. Maps created by using aerial photographs are called ___ maps Ortho photo

2. The Object under study is known as _________ Target

3. The device to detect the Electro Magnetic Radiation is _____ Sensor

II. Match the following

1. Ground Survey  Many Months
2. Remote Sensing  Short span of time
3. Hot air balloon  French Map makers
4. Airplanes  Systematic aerial images

II. Short answers:

1. What is meant by remote sensing?

Remote – far away

Sensing – getting information

Remote Sensing can be defined as the collection of data about an object from a distance.

2. What are the disadvantages of ground survey?

The disadvantages of ground survey

Ground survey of resources is hindered by dense forests, rugged terrain, sandy deserts and unpredictable weather.

It takes many months to study.

3. Mention the basic components of remote sensing.

The four basic components of a remote sensing system are

  1. Target,
  2. Energy source,
  3. Transmission path and
  4. a Sensor.

4. Define GIS.

Geographical Information System (GIS) is a systematic integration of Computer Hardware, Software and Spatial Data, for capturing, storing, displaying, updating, manipulating and analyzing all forms of geographically referenced data.

5. Mention any two applications of GIS.

  • Exploration and mining companies use GIS to find prospective areas for exploration and mining.
  • Power Companies use GIS to monitor and analyse the electricity load for particular area.
  • Transport companies use GIS to locate shortest routes for delivering goods and to save time.

6. What are the uses of GPS?

The uses of GPS

  • Surveying, Map-making, Navigation the main civilian use of GPS.
  • Navigation, Target tracking, Missile Search and rescue are the main military use of GPS.
  • GPS a useful tool for commerce, scientific uses, tracking and surveillance.
  • Farmers, surveyors, geologists perform their work more efficiently, safely, economically.

IV. Answer in a paragraph:

1. Write about Remote Sensing Technology.

Remote sensing can be defined as the collection of data about an object from a distance.

  • Geographers use the remote sensing as a tool to monitor or measure phenomena on the Earth’s lithosphere, hydrosphere, atmosphere and biosphere.
  • Remote sensing is done with the help of mechanical devices known as sensors.These sensors are positioned in helicopters, planes and satellites.
  • Sensors record electromagnetic energy that is reflected back and radiated from the object on the earth surface. Hence, the most effective technology to gather information on any part of the earth within a short span of time.

2. Explain the various components of remote sensing.

Components of Remote sensing:-

The four basic components of Remote sensing system are target, energy source, transmission path and a sensor.

The target is an object or material that is being imaged. Work together to measure and record information about the target.

Without physical contact.

The energy source provides electromagnetic energy to the target.

Classified into two

  • Passive System (that is sun, irradiance from earth’s materials)
  • Active System (that is energy sources such as radar).
  • The electromagnetic radiation interacts with the target, depending on the properties of the target.
  • Transmit information from the target to the sensor.
  • Sensor is a device to detect the Electro Magnetic Radiation can be classified on the basis of energy received into Passive sensors and Active sensors.
  • Passive sensors detect natural radiation that is emitted or reflected by the object. For eg: Cameras
  • Active sensors transmit their own signal and measure the energy that is reflected from the target for example Radar.

3. Explain the process involves in remote sensing technology

Processes involved in Remote Sensing:-

Sun is a Energy Source (A) first requirement which provides electromagnetic energy to the target of things.

Sunrays and Atmosphere (B) as the energy travels from its source to the target interact with, the atmosphere second time from the target to the sensor.

Sunrays and Objects on Earth (C) energy interacts with the target depending on the properties of both the target and the radiation.

Recording of Energy by the Sensor (D) after energy emitted from the target, the sensor collects and records the electromagnetic radiation.

Transmission, Reception and Processing (E) the energy recorded by the sensor has to be transmitted, and processed into an image (hardcopy and/or digital).

Interpretation and Analysis (F) the processed image is interpreted, to extract information about the target which was illuminated.

Application (G) the final process is achieved by applying the extracted information for better understanding.

4. What are the advantages of remote sensing?

Advantages of Remote Sensing:-

  • This system provides a synoptic view of a wide area in a single frame.
  • Remote sensing systems detect features that cannot be reached by human vision.
  • Cheaper and rapid method of acquiring up to-date and continuous information.
  • Helps the planners for formulating policies and programs.

Enable the cartographers to prepare thematic maps like geological maps, soil maps.

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