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Remote Sensing and Geographical Information System for natural disaster management
Samir Kumar Banger
DP Engineer, HOPE Technologies Limited
1 Navjeevan Vihar, New Delhi- 110017, India
kbsamir@yahoo.com
Abstract
Natural disasters are inevitable and it is almost impossible to fully recoup the damage caused by the disasters. But it is possible to minimise the potential risk by developing disaster early warning strategies, prepare and implement developmental plans to provide resilience to such disasters and to help in rehabilitation and post disaster reduction. Space technology plays a crucial role in efficient mitigation and management of disasters. This paper describe the role of remote sensing and Geographical Information System (GIS) in evolving a suitable strategy for disaster management and occupational framework for their monitoring, assessment and mitigation, identifies gap areas and recommends appropriate strategies for disaster management using these technologies.
Introduction
Natural Disasters are inevitable, and Indian subcontinent is prone to all type of Natural Disaster either it is flood, drought, cyclone earthquakes or forest fires etc. Disasters can be classified in several ways A possible sub-division of disaster is: 1) Natural Disasters; 2) Human made disasters; 3) Human induced disasters. Another sub-division is related to the main controlling factors leading to a disaster. These may be meteorologically, geomorphological/geological, ecological, technological, global environmental and extra terrestrial. Another useful distinction that can be made between disaster is regarding their duration of impact and the time of forewarning. Some disaster strikes within a short period with devastating outcomes; others have a slow onset period with equally or even more serious repercussions. According to the available statistics 60% of the total area of Indian subcontinent is venerable to seismic activity of varying intensities, 16% of the country's total area is drought prone. In India 68% of total sown area of the country is drought prone. Coastal areas of India is exposed to tropical cyclones and among all the disaster occur in the country, River floods are the most frequent and often the most devastating.
Remote Sensing and GIS in Disaster Management Mitigation of natural disaster management can be successful only when detailed knowledge is obtained about the expected frequency, character, and magnitude of hazard events in an area. Although, natural disaster have shown in the last decades a drastic increase in magnitude and frequency, it can as be observed that there is a dramatic increase in technical capabilities to mitigate them.
We now have access to information gathering and organizing technologies like remote sensing and GIS, which have proven their usefulness in disaster management. Remote sensing and GIS provides a data base from which the evidence left behind by disaster that have occurred before can be interpreted, and combine with the other information to arrive at hazard maps, indicating which area is potentially dangerous. Using remote sensing data, such as satellite imageries and ariel photos, allows us to map the variabilities of terrain properties, such as vegetation, water, geology, both in space and time. Satellite images give a synoptic overview and provide a very useful environmental information, for a wide range of scales, from entire continents to detail of a few meters. Many types of disasters, such as floods, droughts, cyclones, volcanic eruptions, etc. will have certain precursors that satellite can detect. Remote sensing also allows monitoring the event during the time of occurrence while the forces are in full swing. The vantage position of satellite makes it ideal for us to think of, plan for and operationally monitor the event.
Finally, the impact and departure of the disaster event leaves behind an area of immense devastation. Remote Sensing can assists in damage assessment monitoring, providing a quantitative base for relief operation. After that it can be used to map the new situation and update the database used for the reconstruction of an area. It can help to prevent the occurrence f such disasters again in future.
Disaster Management
The use of remote sensing and GIS has become an integrated, well developed and successful tool in disaster management, as we are having our own earth observation programs, and the requirement for hazard mitigation and monitoring rank high in the planning of new satellites. A very powerful tool in combination of these different types of data is GIS. It is defined as a "powerful set of tools for collecting, storing, retrieving at will, transforming and displaying spatial data from a real world for a particular set of purpose". GIS allows the combination of different kinds of data using models. GIS allows for the combination of the different kinds of spatial data, with non-spatial data, attribute data and use them as useful information in the various stages of disaster management.
A complete strategy for disaster management is require to effectively reduce the impact of natural disaster, which is as referred to as disaster management cycle. Disaster management consists of two phases that takes place before disaster occurs, disaster prevention and disaster preparedness, a three phases that happens after the occurrence of a disaster i.e. disaster relief, rehabilitation and reconstruction. In disaster prevention phase, GIS is used to manage the large volume of data needed for the hazard and risk assessment. In disaster preparedness phase it is a tool for the planning of evacuation routes, for the design of centers for emergency operations, and for integration of satellite data with other relevant data in the design of disaster warning systems. In the disaster relief phase, GIS is extremely useful in combination with Global Positioning System in search and rescue operations in areas that have been devastated and where it is difficult to orientate. In the disaster rehabilitation phase GIS is used to organise the damage information and the post-disaster census information, and in the evaluation of sites for reconstruction. Hence, GIS is the useful tool in disaster management if it is used effectively and efficiently (Pearson et al., 1991).
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