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WS-GIS: Towards a SOA-Based SDI Federation
Fábio Luiz Leite JúniorInformation System LaboratoryUniversity of Campina [email protected]://www.lsi.dsc.ufcg.edu.br
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Outline
Introduction Architecture Example Scenario Conclusion and Further work
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Introduction
The increasing of spatial digital data Petabytes / year in satellite images Digital maps Use of maps in mobile devices
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Main issues: Spatial-aware search engines Data replication should be minimized The use of standards is mandatory
Spatial Data Infrastructure Global, national, and local scale, Using semantic Based on Service-Oriented Architecture
Introduction
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Introduction
SDI – “Technologies, policies, and people necessary to promote sharing of geospatial data throughout all levels of government, the private and non-profit sectors, and the academic community”.
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Introduction
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Introduction
... in the spatial domain base maps, coordinate transformation,
gazetteer, location-based systems, routing, overlay, buffer
how to find out precisely the service a user is requesting ? Keyword-based search ?
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Introduction Web services limitation:
UDDI registry contains little textual information about the underlying services
Keyword-based search may retrieve many irrelevant services just because they contain the addressed keyword
WSDL and UDDI descriptions express almost none of the service semantics
When dealing with spatial data these directories should become spatial-aware
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Our proposal – WS-GIS
A Spatial Data Infrastructure based on SOA for data and services sharing
Users may query a distributed catalog service, semantically enhanced with ontologies
WS-GIS enables spatial search on distributed catalog
Data sharing through some SDI
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Architecture
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Architecture Semantic integration among catalogues
Each SDI defines its own ontology that is used in its catalogues
Assumption: there is a set of concepts which can be shared among the SDIs Clustering semantic communities [Hameed et
al, 2004] Communities are formed through semantic
mapping between SDIs Catalogues that receive the propagated
query make the semantic mapping between the local ontology and the global one
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Semantic integration among catalogues
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Architecture
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ArchitectureService
Description Tool
Service Description
Tool
Geographic MatchmakerFunctionalities
Geographic MatchmakerFunctionalities
Query Propagation
Query Broker
Ontology Reconciliation
Service Providers
Service Designers
Semantic Web servicedescriptions (OWL-S)
Description Repository
SDI Ontology
fin
d W
eb s
erv
ices
submit queries
uses
uses
Service Description
Tool
Service Description
Tool
Geographic MatchmakerFunctionalities
Geographic MatchmakerFunctionalities
Query Propagation
Query Broker
Ontology Reconciliation
Service Providers
Service Designers
Semantic Web servicedescriptions (OWL-S)
Description Repository
SDI Ontology
fin
d W
eb s
erv
ices
submit queries
uses
uses
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Architecture
The catalog service is the core of our architecture Responsible for SDIs integration at local,
national or international scope Each SDI maintains a spatial-aware
catalogue which may find resources locally Communication protocol which propagates
rewritten queries to other SDI catalogues Strategy to maintain the federation Comply with OGC Catalogue API standard
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Example Scenario
Suppose that a user would like visualize a SVG map Regions of Paraíba (AESA) Rivers (and water quality) in Sertão
region (SUDEMA) Roads of the entire state (DER)
AESA SDI Contains Gazetteer service Map conversion service (GML - SVG)
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Example Scenario
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Conclusion
This is a work in progress WS-GIS architecture which aims to
implement a SOA-based SDI A set of spatial services and a federation
of catalogues to enable distributed queries Main purpose
to enable integration of heterogeneous spatial data sets,
by promoting interoperability, flexibility and service chaining
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Further Work
To improve the workflow service Load balancing, Quality of service monitoring, Data provenance and service context
Automatic ontology reconciliation To extend to mobile GIS applications Performance evaluation To analyse the use of grid computing in
our architecture
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Thank you very much!
Questions?
