International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B7. Istanbul 2004
Input data
Output data
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Figure 2. Building Damage Estimation Model (BDEM) process
buildings and transfer the causalities to the safe health centres.
Also the number of Destructed and Evacuate buildings will be
known which helps to estimate the number of human losses and
number of citizens who need sheltering. Financial losses can be
estimated as well. Displaying the results of BDEM, decrease
the costs of gathering data from affected area and minimize the
response time to the earthquake. Although BDEM has a lot of
advantages, it has some difficulties such as dependence on a lot
of environmental and building parameters as well as some pre-
event spatial input data and post-event spatial input data to
process BDEM .So one of the challenges of using this model is
the availability and accessibility of required data as input for
BDEM. In this respect, Spatial Data Infrastructure (SDI) is an
appropriate framework for availability and access to required
data.Currently, research team of K.N.T University of Iran is
working on developing of an SDI conceptual model for disaster
management which can facilitate collection, access, usage and
management of spatial data. This SDI conceptual model creates
an appropriate framework, in which all involved organizations
in disaster response can access to their required spatial data for
disaster response, through partnership effort in data collection
and sharing, before and during disaster. (Mansourian et al,
20042) (Mansourian et al., 2004b).Regards to the most spatial
modeling tasks are very difficult to perform by hand , they are
not usually done unless a computerized system, such as a GIS,
is available. In order to implemente BDEM, designing
appropriate GIS software is essential.
3.5 Web-based GIS software
The prime concern during any disaster management is the
availability of the right spatial information in the right time and
the dissemination of this information to all concerned to make
right decisions. In this way, distributing geospatial information
on a network of information gives a chance to the managers of
organizations to easy access to the information about
earthquake disaster management, any time and any where they
are .So a stand-alone GIS can't be useful in this respect and
carthquake disaster management needs a network-based GIS
with accessing to online data. Therefore a Web-based GIS has
been considered for managing response phase of earthquake
disaster management. Web-based GIS applications involve a
user (the client) who contacts a server for some information.
Commonly two strategies have been used for Web-based GIS
applications .In the first extreme the server passes data and
mapping applications (usually Java applets) to the client means
that server supplies the data and the programs, but all GIS
functions are carried out on the client side (client-side strategy).
In the second strategy, the client indicates the type of map of
functions that wishes to execute, and the server passes back the
map the client request (server-side strategy). Several factors
influence the strategy of Web-based GIS .In client-side
strategy; server passes data and Java applets to the client, so it
is functional and easy to use, but this strategy has some
drawbacks for example, client-side strategy is not useful for
transmitting huge data, because it takes a long of time, also it
needs enough disk space and/or RAM to store in client-side. It
doesn't concern about data security as well, because people can
download raw data and may be there is some sensitive data
which it shouldn't be download by them. Server-side strategy
hasn't these kinds of difficulties. However, it is not without its
drawbacks. For example, if site receives a lot of traffic, the
server is going to be very busy processing for each user's
request for a map so, this strategy is not suitable if server
overloaded. As a lot of data gathered from variety of
organizations in GIS database of earthquake disaster
management and it is necessary to access to the right data for
disaster managers, so data security is an important aspect in this
respect. Therefore a server-side strategy has been chosen for
developing the Web-based GIS system. (See figure.3)
Server
Transfer the requested map Client
Request for a Map
Figure 3. Server-side strateg
While the purpose of designed earthquake disaster management
system is to provide the managers and potential users requests,
the Web-based GIS become useless for the others users. With
this assumption, the problem of overloading of the server-side
strategy will be faded. Selecting suitable software is an
important step in a successful implementation. For the purpose
of managing response phase of earthquake disaster a Web-based
Earthquake Disaster Management GIS software (EDM) has
been developed by using GlSengine and programming
languages such as visual basic, HTML and Java script (See
figure.4).
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