dstt report - ogc services may 8, 2002page 1 allan doyle dstt report ogc services dstt report ogc...
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DSTT Report - OGC ServicesMay 8, 2002 Page 1Allan Doyle
DSTT ReportOGC ServicesDSTT Report
OGC & GRID Services
Allan DoyleNASA/II
May 8, 2002
CE SCommittee on Earth Observation SatellitesWorking Group on Information Systems and Services
DSTT Report - OGC ServicesMay 8, 2002 Page 2Allan Doyle
“If you don’t understand first off and it makes your mind go numb, you’re safe to ignore it, it will never work”
• Dave Winer at InfoWorld Next Generation Web Services Conference, January 2002
DSTT Report - OGC ServicesMay 8, 2002 Page 3Allan Doyle
Info
OGC Services
http://www.intl-interfaces.net/servicemodel
GRID Services
http://www.globus.org/ogsa/
DSTT Report - OGC ServicesMay 8, 2002 Page 4Allan Doyle
1999 2000 2001 2002
OpenGIS® Abstract SpecTopic 12 - The OpenGIS
Service Architecture
Architecture SIG
WWW Mapping SIG
Basic Service ModelDiscussion Paper
Web Registry ServicesDiscussion Paper
CEOS WTF-GOFC
WMT-1 IP2000 (WMT-2) IP2001 (OWS-1) OWS 1.2
OpenGIS® Catalog Interface Implementation Specification 1.0
OpenGIS® Catalog Interface Implementation Specification 1.1
ebXML
Microsoft .NET
UDDI
CEOS WTF (??)
NASA
Industry
OGC
ECHO
Grid Services
Services Time Line
J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D
ServicemodelAd Hoc
GCMD (SERFs)
DSTT Report - OGC ServicesMay 8, 2002 Page 5Allan Doyle
A. Search for Services first• Decision support community view ?
B. Search for Data first• Science community view ?
Technical ChallengesData vs. Services
<service name=WMS> <layer name=“FirePoint”>
… <dataURL=ftp://…>
ClientApplication
GetFeature GetMap GetCoverage
ServiceCatalog
WFS
FeatureDataStore
WMS
MapDataStore
WCS
CoverageDataStore
FusionServices
GeocodeGeoParseGeoLink
DataCatalog
<dataset name=MODIS> <Online_Resource name=“WMS”> http://foo.org/wms.cgi?REQUEST=…
Develop metadata and discovery mechanisms that can support both service-centric and data-centric modes.
DSTT Report - OGC ServicesMay 8, 2002 Page 6Allan Doyle
Interface Type MetadataType HierarchiesInterface Instance MetadataData Type MetadataData Instance MetadataCombinations of Data/InterfaceServices & Service MetadataControlled Vocabularies Catalogs & Registries
End-user
WMS
Single Service
WMS
WFS
Multiple ServiceSame Data
CoordTrans.
Service OnlyNo Data
FTP
Data OnlyNo Service
Catalog
CatalogService
InventoryAccess
http://ceos.org100,50,2300,75.4X=56
Directory
Inventory
LargeData System
i n t e r n e t
Interface Type MetadataType Hierarchies
Interface Instance MetadataData Type MetadataData Instance MetadataCombinations of Data/InterfaceServices & Service MetadataControlled Vocabularies
Catalogs & Registries
Interface Type MetadataType HierarchiesInterface Instance MetadataData Type MetadataData Instance MetadataCombinations of Data/InterfaceServices & Service MetadataControlled Vocabularies Catalogs & Registries
End-user
WMS
Single Service
WMS
WFS
Multiple ServiceSame Data
CoordTrans.
Service OnlyNo Data
FTP
Data OnlyNo Service
Catalog
CatalogService
InventoryAccess
http://ceos.org100,50,2300,75.4X=56
Directory
Inventory
LargeData System
i n t e r n e t
Technical ChallengesMetadata & Vocabularies
DSTT Report - OGC ServicesMay 8, 2002 Page 7Allan Doyle
OGC Services• HTTP GET/POST
based interfaces• Service instances
provide their own metadata service descriptions (“Capabilities”) via XML
• Filter parameters allow selection of subsets of source data
• Output formats advertised by each service instance
http://ceos.org100,50,2300,75.4X=56
WMSmaps
WFSfeature data
WCScoverage data
<Roads> <Road> <gml:name>M11</gml:name> <gml:centerLineOf> <gml:LineString srsName="EPSG:4326"> <gml:coordinates> 0,5.0 20.6,10.7 80.5,60.9 </gml:coordinates> </gml:LineString> </gml:centerLineOf> <classification>motorway</classification> <number>11</number> </Road></Roads>
DSTT Report - OGC ServicesMay 8, 2002 Page 8Allan Doyle
OGC Service Registry Concepts• Registry should be
able to handle any kind of service.
• Should allow searches against more criteria than WMT-1 catalog
• Each service’s metadata should be composed of common elements where possible
• Initially described in the IP2000 Basic Service Model
WMSmaps
WFSfeature data
WCScoverage data
<Roads> <Road> <gml:name>M11</gml:name> <gml:centerLineOf> <gml:LineString srsName="EPSG:4326"> <gml:coordinates> 0,5.0 20.6,10.7 80.5,60.9 </gml:coordinates> </gml:LineString> </gml:centerLineOf> <classification>motorway</classification> <number>11</number> </Road></Roads>
Metadata
Registry<Roads> <Road> <gml:name>M11</gml:name> <gml:centerLineOf> <gml:LineString srsName="EPSG:4326"> <gml:coordinates> 0,5.0 20.6,10.7 80.5,60.9 </gml:coordinates> </gml:LineString> </gml:centerLineOf> <classification>motorway</classification> <number>11</number> </Road></Roads>
Metadata
Metadata
DSTT Report - OGC ServicesMay 8, 2002 Page 9Allan Doyle
OWS1 Service Model Issues• Two competing
registry information models: UDDI and ebXML
• Two competing means of constructing registries: XML database and OGC Stateless Catalog
• Three competing Metadata content models: R4, R7, and R8
• Not enough consensus, fragmented results
WMSmaps
WFSfeature data
WCScoverage data
<Roads> <Road> <gml:name>M11</gml:name> <gml:centerLineOf> <gml:LineString srsName="EPSG:4326"> <gml:coordinates> 0,5.0 20.6,10.7 80.5,60.9 </gml:coordinates> </gml:LineString> </gml:centerLineOf> <classification>motorway</classification> <number>11</number> </Road></Roads>
Metadata
Registry<Roads> <Road> <gml:name>M11</gml:name> <gml:centerLineOf> <gml:LineString srsName="EPSG:4326"> <gml:coordinates> 0,5.0 20.6,10.7 80.5,60.9 </gml:coordinates> </gml:LineString> </gml:centerLineOf> <classification>motorway</classification> <number>11</number> </Road></Roads>
Metadata
Metadata
DSTT Report - OGC ServicesMay 8, 2002 Page 10Allan Doyle
Navigating theWeb Services Industry
The Web Services industryBig players see big moneyMuch jockeying for position & mindshareMany overlapping/competing standardsNot many cross-vendor deployments yetVery complex set of issues
(for what seems like a simple concept!)
OASIS
WS-I
W3C
Standards OrganizationsW3C
World Wide Web Consortium
OASIS Organization for the Advancement of Structured Information Standards
WS-I Web Services Interoperability Organization
IETF Internet Engineering Task Force
Global Grid ForumMajor Vendors
Microsoft .NET (not an acronym…)
Sun ONE (Open Network Environment)
IBM Websphere (Based on Apache web server)
AcronymsSOAP
Simple Object Access Protocol
UDDI Universal Description, Discovery and Integration
ebXML Electronic Business using eXtensible Markup Language
WSDL Web Services Description Language
OGSAOpen Grid Services Architecture
Micro
soft
Sun
IBM
DSTT Report - OGC ServicesMay 8, 2002 Page 11Allan Doyle
Some key points
• Most real, operational web services exist on intranets and extranets.
• There is little evidence of web services on the “open” internet.
• Web services are not about “the web”.
• Web services are producer-oriented tools. Consumers of web services see a carefully controlled entry point. End-users generally see portals.
DSTT Report - OGC ServicesMay 8, 2002 Page 12Allan Doyle
The Eight Fallacies of Distributed Computing
How does the GRID measure up?Peter Deutsch• Essentially everyone, when they first
build a distributed application, makes the following eight assumptions. All prove to be false in the long run and all cause big trouble and painful learning experiences.
2. Latency is zero3. Bandwidth is infinite4. The network is secure5. Topology doesn't change6. There is one administrator7. Transport cost is zero8. The network is homogeneous
– http://java.sun.com/people/jag/Fallacies.html
1. The network is reliable
DSTT Report - OGC ServicesMay 8, 2002 Page 13Allan Doyle
• How hard is it to wrap an OGC service in a GRID wrapper?
• How hard is it to build OGC services that are clients of GRID services?
• Can an OGC service be moved to where the data is?• Can an OGC service be moved to where the compute
cycles are available?
Wrapping
network
service
DSTT Report - OGC ServicesMay 8, 2002 Page 14Allan Doyle
Think of this model
portal
GRID Web