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Effective proactive disaster management in Nigeria
would depend, to a large extent, on the use of the
Geographic information system (GIS) and maps.
The GIS is a computer system that is designed to
assemble, store, manipulate and display
geographically referenced information. The system is
capable of representing data in their respective
locations. In practice, therefore, a GIS combines
layers of information about a place to assist
disaster managers in understanding a particular
area and disaster.
The GIS is used to ascertain the best location for a
new settlement, analyze environmental damage and
view flood peaks in a city to effectively detect a
pattern. In addition, a GIS can be used for
scientific investigations. Disaster managers also
use the GIS to calculate emergency response time,
just as it can be used to find wet lands that need
to be protected from pollution.
With GIS, maps and tabular data are stored for the user
to produce customized maps. The
user could also perform specialized data based
queries, analyze complex relationships, apply models
and take decisions on real life problems confronting
specific areas. Maps are essential at all stages of
disaster management cycle: prevention,
mitigation, preparedness, response and recovery. It
is important to undertake a range of activities such
as risk assessment, scenario analysis or analysis of
consequences, forecast and projection, dissemination
of information, allocation of personnel, equipment
and other resources, reaching various affected areas
by relief personnel; damage assessment and so on.
Maps play a critical role in all these activities.
Maps have been used for centuries. Village maps
based on land survey and road maps have been there
since ages. In recent times, availability of
powerful computers, digitized maps and development
of GIS has transformed the design, quality and
utility of maps. GIS in places like NEMA can help us in organizing,
analyzing, displaying and verifying enormous data
that help decision making.
The role of mapping for disaster management can be
analyzed with reference to the following phases:
• Hazard assessment and vulnerability analysis,
mitigation and preparedness
• Pre-disaster phase
• Response
• Loss and damage assessment
• Rehabilitation and reconstruction
Hazard assessment and vulnerability analysis are
fundamental to disaster management planning. It is
necessary to identify geographical areas that are
likely to be affected by hazards such as flood,
drought, fire outbreak and erosion. Vulnerable and
risky areas in the context of various types of
disaster need to be identified and mapped with a
view to planning for prevention, mitigation and
emergency response measures. Maps will show areas
having different degrees of vulnerability and those
prone to multiple disasters that will help the
disaster manager prioritize the response mechanism.
With Geographical Information Systems, which
link maps with database, it would be possible to
have simulation models that can be useful at various
stages. With the help of NEMAGIS, we can analyze
disaster over time and space. Based on such an
analysis, one can assess the likelihood of such
phenomena at different locations and over time. This
can help prevent certain occurrences and mitigate
the effect of such phenomena. Mitigation measures
will have to be taken in areas that are more prone
to hazards like flood, drought and erosion. Maps can
also be updated as soon as the
linked database is updated.
Based on the above analysis mitigation and
preparedness activities can be planned. For example,
enforcement of resistant design is essential, as a
mitigation measure, for areas with higher
probability of hazard.
The pre-disaster phase is defined in a limited
sense. It is the period after a warning or an early
warning of a disaster and before the actual
occurrence of a disaster. During this period, with
the help of maps , scenarios can be analyzed and
response measures can be planned. Evacuation route
can be planned and displayed for use by emergency
managers.
Action during the response phase can be a
continuation of that during the alert period. Once
we know likelihood occurrence of a disaster, the
response, for example search and rescue activities,
can be planned and organized with the help of maps
which show urban settlement, vital installations,
houses, population and so on.
The role of maps in loss and damage assessment does
not need any emphasis. In the event of a disaster,
the assessment of damage may have to be done in
phases. Immediately after the disaster, questions
are asked regarding the number of deaths, the number
of injured persons, loss of property etc. With the
help of GIS we can have broad and quick estimates of
area, population and the vital installations
affected. At a later stage when a detailed survey
and damage assessment are carried out, the
consistency and reliability of the data can be
checked with GIS based analysis.
Mapping is essential even during relief,
rehabilitation and recovery phases (after a
disaster). In the event of a major disaster
affecting vast areas and* a large population, it is
necessary to plan relief and rehabilitation
activities using maps. The task becomes
easier and more systematic if maps are linked to
database.
Mapping has become an integral part of a modern decision
support system. Disaster management involves complex
issue of decision making, because most of the
decisions are taken under an uncertain environment.
In this context, convergence of imagery, information
and maps has immense potentials. It can facilitate
better policy analysis, preparedness and quicker
response that can help us save lives and property.
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