SEE/SAW-GEO:
Towards Orchestration of Secure Gridenabled Geospatial Web Services
David Fairbairn1, Philip James1, Chris Higgins2, Gobe Hobona1
1 Newcastle
University
2 EDINA
Outline
• Background
• Geospatial and Grid Services
• Workflows
• Semantic Support
• SAW-GEO Architecture
• Conclusions
Background
• Open Geospatial Consortium
• Open Grid Forum, OASIS, W3C etc
• JISC Grid/OGC Collision Programme
• SEE-GEO and SAW-GEO projects
• NIEeS Grid GIS Working Group
• Facilitated collaborations between project partners
Geospatial Services
• OGC Services Architecture
• Same as ISO19119
• Human interaction services
• Geographic viewers
• Model/information management services
• Web Feature Services (WFS), Web Coverage Services (WCS), Web Map
Service (WMS), Catalogue Services for the Web (CS-W)
• Workflow/task management services
• Workflow Enactment Services
• Processing services
• Web Processing Services (WPS)
• Others: Communication and System management services
Grid Services
• Service-Oriented Architecture (SOA)
• Web Services Description Language (WSDL), Simple Object Access
Protocol (SOAP)
• Resources Access
• Stateful vs. Stateless
• Open Grid Services Architecture (OGSA)
• Web Services Resource Framework (WS-RF)
• GetResource, QueryResource etc
• Web Services Interoperability (WS-I)
Workflows
• Recognised by both ISO19119 and OGSA
• Transparent, translucent & opaque chaining
• Business Process Execution Language (WS-BPEL)
• Supported by Oracle, IBM, Sun Microsystems, Active Endpoints etc
• Partners, Activities and Variables
• Others: SCUFL through Taverna
OGC OWS-4 GeoProcessing Workflow
WPS 1
Generalise
BPEL
engine
client
WPS 2
Clip
Based on OGC OWS-4 GeoProcessing Workflow Scenario
WFS
Adding Semantic Support to Workflows
• Semantically Aware Workflow Enactment
• Modify a feature collection according to assertions in an
ontology
• Perform semantic similarity computations between workflow
variables
• Web Ontology Language (OWL)
• Querying OWL Knowledge Bases through SPARQL
• Semantic functions performed by the Workflow Engine, involving
OWL and WFS
SAW-GEO Architecture
Workflow Enactors Considered
• Intalio PXE
• Incorporated into Apache ODE – still at incubator stage
• Netbeans Enterprise Pack
• Limitations in handling varying namespaces e.g. OGC schemas
• Eclipse
• No runtime engine offered, only a BPEL editor
• ActiveBPEL Open Source by ActiveEndpoints
• Taverna
• No support for BPEL. Limitations when handling varying namespaces
ActiveBPEL Workflow Engine
SEE-GEO
• SEcurE access to GEOspatial services
• Aiming for access to GI via the National Grid Service
• Shibboleth
• WS-Security
• GSI
• OGC Web Services
• Partners: EDINA, NeSC, NCeSS, MIMAS
• Main deliverables are a report and 3 demonstrators:
• National datacentre
• Social Science (NCeSS)
• Orchestration (Newcastle)
Conclusions
• GeoProcessing Workflows have implications for copyright
• Possible to integrate OGC services into Grid-based Workflows
• Limitations in OGC specifications regarding SOAP binding
• An OGC specification for SOAP binding would be a positive
development
• BPEL suitable for orchestrating grid-based OGC web services
Future Work
• SAW-GEO project expected to conclude April 2008
• Implementation Phase next
• Possible participation in the OGC OWS-5 Secure GeoProcessing
Workflow Theme
Acknowledgements
• SEE-GEO and SAW-GEO are funded by the Joint Information
Systems Committee (JISC) through the Grid/OGC Collision
Programme