Remote sensing- GIS and its application

Remote Sensing

Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object and thus in contrast to on-site observation.

In current usage, the term “remote sensing” generally refers to the use of satellite- or aircraft-based sensor technologies to detect and classify objects on Earth, including on the surface and in the atmosphere and oceans, based on propagated signals.

Remote sensing is used in numerous fields, including geography, land surveying and most Earth Science disciplines for example, hydrology, ecology, oceanography, glaciology, geology.It also has military, intelligence, commercial, economic, planning, and humanitarian applications.

GIS

Geographic Information System (GIS) is a computer based application of technology involving spatial and attributes information to act as a decision support tool.

It keeps information in different layers and generates various combinations pertaining to the requirement of the decision-making. In the recent times, GIS has emerged as an effective tool in management of disasters since, geo-spatial data and socio-economic information need to be amalgamated for the better decision making in handling a disaster or to plan for tackling a disaster in a better way.

Applications:

Disaster Management

The different line departments and agencies who are stakeholders in the disaster management process could utilize GIS. Some basic hardware like computer system, printer, network systems, along with GIS software is required to set up the GIS in any organisation.

Objectives:

The prime objectives of developing the GIS database are to help disaster managers at State, District and Block level for:

i) Pre-disaster planning and preparedness

ii) Prediction and early warning

iii)  Damage assessment and relief management

GIS combines layers of information on various themes to enable the managers to take the most appropriate decisions under the given circumstances. For disaster management, a GIS database could be a useful managerial tool for various reasons, some of which are as under:

• Disaster Managers could generate maps both at micro and macro level indicating vulnerability to different extents under different threat perceptions.
• Locations likely to remain unaffected or remain comparatively safe could be identified.
• Alternate routes to shelters, camps, and important locations in the event of disruption of normal surface communication could be worked out.
• Smooth rescue and evacuation operations could be properly planned.
• Rehabilitation and post-disaster reconstruction works could be properly organized.
• Locations suitable for construction of shelters, godowns, housing colonies, etc. can be scientifically identified.
• Areas where no construction should be taken up or existing habitations require relocation could be identified.

Hydrology

Remote sensing of hydrologic processes can provide information on locations where in situ sensors may be unavailable or sparse. It also enables observations over large spatial extents. Many of the variables constituting the terrestrial water balance, for example surface water storage, soil moisture, precipitation, evapotranspiration, and snow and ice, are measurable using remote sensing at various spatial-temporal resolutions and accuracies. Sources of remote sensing include land-based sensors, airborne sensors