Building a Distributed Disaster
Management System
Xiannian Chen
WV GIS Technical Center
Department of Geology and Geography @ WVU
Disasters
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Yangzi River Floods (China, 1998.14 million
people homeless)
911 Terrorist Attack (USA, 2001. About 3000
people killed)
Indonesian Tsunami (2004. About 230,000
people killed)
Hurricane Katrina (USA, 2006. At least 1,836
people killed)
Wenchuan 512 Earthquake (China, 2008.70,
000 people killed and 5 million people homeless)
Haiti Earthquake (Haiti, 2010. About 230,000
people killed and 1million people homeless)
Characteristics of Disasters
Large scale, which means two or more
jurisdictions will be involved.
 Rapid onset, which means the events
give people no time or short time to
prepare to evacuate.
 Dynamic, which means disasters evolve
as they progress.
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Disaster Management Phases
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Four phases overlaid in a continuous
cycle.
◦ Response
 Rescue
 Relief
◦ Recovery
◦ Mitigation
◦ Preparedness
Needs in Disaster Management
The need for efficient and effective access
to decision-making information relevant
to all phases of emergency management;
 The need for collaboration among the
agencies at different levels;
 The need for the collaboration of
different agencies that are in charge of
different thematic data.
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Challenges that traditional GIS faces
Built on stand-alone platform.
 Hard to communicate among systems.
 Users at one end of internet/intranet
cannot share information with users at
the other end.
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◦ e.g. The in-house GIS system/model cannot
accept the dynamic input from the in-field
first-time responders. Managers in the
emergency operation center cannot make the
right decisions without real-time information.
How Distributed GIS overcome the
challenges?
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As the integration of geospatial data,
geospatial tool, and distributed computing
technologies, distributed GIS computing
can overcome the challenges, such as realtime data collection and updating, realtime information dissemination,
distributed information access, distributed
processing services access.
Distributed GIS System
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Distributed GIS is geospatial technologies
combined with distributed computing
technologies and the standards of Internet.
Internet GIS
◦ Internet refers to the network infrastructure.
◦ Web-based GIS is one kind of Internet GIS
 Based on HTTP protocol, which is one of many
applications that runs on Internet
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Mobile GIS
◦ Wireless GIS
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The core of Distributed GIS is geospatial
web service
Geospatial Web Services
SOAP (Simple Object Access Protocol) web
service, based on Service Oriented
Architecture (SOA)
 HTTP (HyperText Transport Protocol) web
service, based REST Oriented Architecture
(ROA)
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OGC’s SOAP Web Service
OGC: Open Geospatial Consortium
 Data sharing web services.
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◦ Web Map Service (WMS)
◦ Web Feature Service (WFS)
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Processing sharing web services
◦ Web Processing Services (WPS)
REST Web Services
REST (Representational State Transfer)
Roy Fielding in 2000.
 Basically means that each unique URL is a
representation of some object.
 Get the contents of that object by using
an HTTP GET.
 Use a POST, PUT, or DELETE to modify
the object.
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REST Web Services Characteristics
Client-Server
 Stateless: each request from client to server must contain all
the information necessary to understand the request.
 Cache: to improve network efficiency, responses must be
capable of being labeled as cacheable or non-cacheable.
 Uniform interface: all resources are accessed with a generic
interface (e.g., HTTP GET, POST, PUT, DELETE).
 Named resources - the system is comprised of resources
which are named using a URL.
 Interconnected resource representations: the representations
of the resources are interconnected using URLs
 Layered components: intermediaries can be inserted between
clients and resources to support performance, security, etc.
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REST vs. SOAP
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REST over SOAP:
◦ Lightweight – not a lot of extra xml markup
◦ Human Readable Results
◦ Easy to build – no toolkits required
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REST is the trend in web service.
◦ “Use SOAP to wash, and you REST when you
are tired.”
◦ All of the major web services on the Internet
now use REST: Twitter,Yahoo’s web services,
Flickr, and so on.
Types of REST Web Services
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Types of REST services
◦ REST data services
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Image services
Map services
Geodata services
Geocoding services
Geometry service
◦ REST geoprocessing services
 Geoprocessing services
REST Data Services
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Purpose:
◦ Data collection, updates, dissemination, and access
Data collection and updates
◦ GPS for thematic vector data
◦ Improved Remote Sensing for basemap and imagery
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Data dissemination and data access
◦ Map Cache
 Provides fast access to cached image or map service
◦ Optimized map service
 Provides fast access to vector data
REST Geoprocessing Services
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Purpose
◦ Provides Internet access to sophisticated GIS
Desktop functionalities, such as functionalities
in spatial analyses, functionalities 3D analyses,
functionalities network analyses, and the
combinations of functions in those
extensions.
Features of Distributed Disaster
Management System
Easier dynamic (real-time) data sharing
 Faster map rendering
 Rich desktop GIS functionalities
integrated
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Questions and comments?