GIS and Remote sensing

What is Remote sensing and GIS?

In this tutorial, You will learn all about gis and remote sensing, the importance of remote sensing and gis, the differences between gis and remote sensing, and what is remote sensing used for?

What is GIS?

GIS stands for Geographic Information System. According to Tomlin GIS may be defined as a configuration of both software as well as hardware which are specially designed for the use and maintenance of cartographic data. 

GIS is described as an information system that is used to take input, store, retrieve, manipulate, analyze it and finally generate output geographically referenced data or geospatial data, in order to maintain and support decision making toward planning and management of different things like land use, natural resources, environment, transportation, urban facilities, and other administrative records.

The source of digital data for use in GIS is created by Remote Sensing technology on board of satellites and other aircraft.

The geographic Information System GIS consists of geographic and information systems. Geography is the study of geospatial patterns and processes. It seeks to identify and account for the location and distribution of human and physical phenomena on the earth surface.

The information system is a combination of people, software & hardware, and communication device. The people interact with the software and hardware which keeps electronic records. The records are kept digitally in the memory.

First, the input of the source file is fetched, and then there is a recording of electronic data is done and then the output data is shown. The records are then kept as documentation and indexing so that it is easier to revisit in the future.

Components of Geographic Information System

  1. Hardware
  2. Software
  3. Procedures
  4. Data
  5. User

Hardware - It consists of a computer hardware system on which the GIS software runs. The GIS runs on the spectrum of computer systems ranging from Personal Computers (PCs) to multi-user supercomputers. 

The hardware for GIS consists of input devices such as a digitizer, scanners, and GPS receivers, storage devices such as magnetic tapes and disks, CD ROMs, and other optical disks.

Software - Software refers to the programs run on computers, these include programs to manage the computer and to perform specific functions. 

GIS software gives the functions and tools that are essential for storing, analyzing, and displaying geographic information. Some popular GIS Softwares are ArcGIS, Mapinfo, Geometrica, and many others.

Procedures - A computer system for GIS consists of hardware, software, and procedures developed to support the data capture (as an input), storage, processing, modeling, analysis, and presentation of geospatial data.

Besides the technical components like hardware, software, and databases, institutional framework and policies are also important for functional GIS.

Data - Data are named as geospatial and attribute data in his. The GIS facilitates the integration of spatial and attribute data and this makes them unique in contrast to other database systems.

The source of the spatial data are digitized maps, aerial photographs, and satellite images. Attribute data sources are statistical tables and other related documents. Geographic data and related tabular data can be collected by surveying or purchasing from a commercial data provider.

User - The role of the user is to select pertinent information to set necessary standards, to design cost-efficient updating schemes to analyze GIS output for the relevant purpose and plan the implementations.

The users are always the peoples who plan, implement, and operates the systems as well as to make the decision based on the output.

What is Remote sensing?

Remote Sensing is made from two words namely "remote" which means "something which is far away" and "sensing" which means "gathering information or getting data".

Remote sensing is the science of gathering information about the Earth's land and water areas with the help of images captured by using sensing devices. 

The remote sensing devices do not come in contact with the Earth. It is operated from a remote location. It is a technology of acquiring information about earth surface without actually being in contact with it.

How Remote Sensing process work?

Remote sensing process works in 7 steps
  1. Energy source
  2. Radiation and atmosphere
  3. Interaction with the target
  4. Recording of energy by the sensors
  5. Transmission, reception, and processing
  6. Interpretation and analysis
  7. Application
Energy Source - Energy source is the first basic requirement for the remote sensing process. The energy source illuminates or gives electromagnetic energy to the target.

Radiation and atmosphere - As the energy moves from its origin to the target, firstly it will come in contact with the atmosphere, this interaction may take place a second as the energy moves from the target to the sensor.

Interaction with the target - Once the energy makes its way to target through the atmosphere, it interacts with the target depending upon the properties of both the target and the radiation.

Recording of energy by the sensors - After the energy has been scattered by, emitted from the target, there is a requirement of sensors to collect and record the electromagnetic radiation without coming in contact with it.

Transmission, reception, and processing - The energy required by the sensors have to be transmitted (in electronic form) to receive and processing section where the data are produced into an image (hard copy and digital).

Interpretation and analysis - The proceed image is interpreted in two types visually and digitally to extract information about the target which was illuminated.

Application - The last component of the remote sensing process is finished when we apply the knowledge or information. We have been able to obtain from the imagery about the destination in order to better explain and expose some new information.

Historical development of Remote Sensing Process

The history of the remote sensing process began with the invention of the photograph. The term photograph is derived from two words 'phos' means light and 'graphy' means 'writing'.

  1. In the year 1038 AD, AL Hazen an Arabian mathematician explains the principle of camera obscura to observe a solar eclipse.
  2. In the year 1666, Sir Issac Newton experimenting with a prism and found that when a white color passes through a prism then it splits into seven different colors.
  3. In 1800, Sir William Herschel measures the temperature of light split with a prism into a spectrum of visible colors. He had discovered thermal infrared electromagnetic radiation.
  4.  In 1858, GFT Nadar takes the first aerial photograph from a captive balloon from an altitude of 1200 feet in Paris.
  5. In 1889, Arthur Batut takes the first aerial photo by using a kite in France.
  6.  In 1903, BP Crop uses pigeon to transmit a message and take an aerial photograph.
  7. In 1957, Sputnik I was launched by Russia. It is World's first artificial satellite launched on 4 October 1957.
  8. In 1985, Explorer I was launched by the USA.
  9. In 1970, Dong Fang Hong I was launched by China.
  10. In 1975, Aryabhatta was launched by India.
  11. In 1979, Bhaskar I was launched by India.
  12. In 1980, Rohini I was launched by India.
  13. In 1982, Insat 1A was launched by India.
  14. In 1998, IRS (Indian Remote Sensingwas launched by India.
  15. In 2001, GSAT I was launched by India.
  16. In 2004, EDUSAT was launched by India.
  17. In 2005, Cartosat was launched by India.
  18. In 2008, Chandrayaan was launched by India.
  19. In 2013, Mangalyan was launched by India (5th November 2013-24 September 2014).

Applications of Remote sensing

  1. Agriculture
  2. Forestry
  3. Geology
  4. Hydrology
  5. Sea ice
  6. Land cover and land use
  7. Oceans and Coastal monitoring
  8. Atmosphere monitoring
  9. Meteorological parameters measurement
  10. Developing online mapping services

The field of GIS and Remote sensing is the technology of today.
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