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OGC Catalog Service for the Web (CS/W): experience in NASA John D. Evans, Ph.D. NASA Geosciences Interoperability Office (GIO) Earth.

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Presentation on theme: "OGC Catalog Service for the Web (CS/W): experience in NASA John D. Evans, Ph.D. NASA Geosciences Interoperability Office (GIO) Earth."— Presentation transcript:

1 OGC Catalog Service for the Web (CS/W): experience in NASA John D. Evans, Ph.D. NASA Geosciences Interoperability Office (GIO) Earth Science Applications Division -/- Global Science & Technology, Inc. Goddard Space Flight Center, Greenbelt, MD

2 Introduction & overview OGC CS/W specification: Spring 2004 OGC CS/W specification: Spring 2004 – (After many iterations) OGC ebRIM profile: Fall 2005 OGC ebRIM profile: Fall 2005 NASA experimenting with CS/W since Fall 2004 NASA experimenting with CS/W since Fall 2004 Two implementations in particular: Two implementations in particular: – ECHO CS/W connector (Center for Spatial Information Science & Systems [CSISS], George Mason University) – Earth Science Gateway (NASA Geosciences Interoperability Office [GIO] & Compusult Ltd.) Implementation experience Implementation experience – Insights, opportunities, and challenges

3 GMU / CSISS experience with CS/W Birds eye view Birds eye view - From Bai, Y., et al., 2007: Towards a Geospatial Catalogue Federation Service, Photogrammetric Engineering & Remote Sensing 73 (6), pp

4 GMU / CSISS experience with CS/W Inside the Catalogue Federation Service Inside the Catalogue Federation Service - From Bai, Y., et al., 2007: Towards a Geospatial Catalogue Federation Service, Photogrammetric Engineering & Remote Sensing 73 (6), pp

5 RegistryObject Classification ClassificationSchema …… Association ServiceBindings RegistryEntry Service ExtrinsicObject CSWExtrinsicObject RepositoryItem Service Info. Model (ISO 19119) Dataset Info. Model (ISO 19115) NASA EOS Core System (ECS) Slot GMU / CSISS experience with CS/W ebRIM model extends OGC CSW for geospatial resources ebRIM + OGC Catalogue Service for CS/W + OGC Catalogue Service for ISO 19115/19119

6 GMU / CSISS: CS/W bridge to ECHO Connects to the full, operational ECHO Connects to the full, operational ECHO Partial ECHO–ebRIM mapping. Emphasis: Partial ECHO–ebRIM mapping. Emphasis: – CS/W core queryables (Dublin Core) – Granules (not Collections) Performance issues: Performance issues: – ECHO not fully optimized for granule-level search – ECHO 8 responds to most queries from CS/W connector in under 2 minutes (used to be worse) – ECHO 9 may further improve query performance Multiplicity of schemas poses addl challenges Multiplicity of schemas poses addl challenges – CS/W used as a hub for several different catalogs

7 NASA / GIO Earth Science Gateway (ESG)

8 Earth Science Gateway (ESG) Service Manager OGC WMS Servers Service Manager Service Registry Database (Oracle) Web Publishing Client OGC WFS Servers OGC WCS Servers External Applications/Clients OGC CSW Requests - GetCapabilities (1) - GetRecords (2) OGC CSW Transactions (3) - Insert - Update - Delete OGC Repository Extensions - GetRepositoryItem (4) - PutRepositoryItem (5) Capabilities XML Document (1) Transaction Status (3) Search Results (2) Repository Item (4) Repository Status (3)

9 OGC WMS Servers Service Manager Service Registry Database (Oracle) Web Publishing Client OGC WFS Servers OGC WCS Servers External Applications/Clients OGC CSW Requests - GetCapabilities (1) - GetRecords (2) OGC CSW Transactions (3) - Insert - Update - Delete OGC Repository Extensions - GetRepositoryItem (4) - PutRepositoryItem (5) Capabilities XML Document (1) Transaction Status (3) Search Results (2) Repository Item (4) Repository Status (3) Earth Science Gateway (ESG) Service Manager ESG portal uses CS/W internally for all catalog access ESG portal uses CS/W internally for all catalog access – Search – Publish – Harvest Public interface available for other CS/W clients Public interface available for other CS/W clients Simple HTML client can query other CS/W servers Simple HTML client can query other CS/W servers

10 ESG in OGC Web Services Testbed 3 Successful connections from a Refractions Research CS/W client (Nov. 2005) Successful connections from a Refractions Research CS/W client (Nov. 2005) Key challenge: reconciling different ebRIM representations Key challenge: reconciling different ebRIM representations – E.g., WMS Layer Extrinsic Object: is its ObjectType Layer?WMS_Layer? or Data_Set? – A guessing game; create equivalencies to fit queries coming from different clients – Changing an ebRIM type name can be a headache Another challenge: maintaining performance Another challenge: maintaining performance – Query response slowed a lot at 100k-200k records. – Server-side workarounds: temp tables; caching; returning summaries rather than full records

11 ESG in OGC Web Services Testbed 4 UAV EO-1

12 Service Binding Classification ExtrinsicObject objectType = Geometry ExtrinsicObject objectType = Context Document (WMS only) HasFootprint Offers HasContext Service Binding Extents User OffersService ExtrinsicObject objectType = Dataset Description (Metadata Document) HasFootprint Describes Classification uuid = parent uuid = classified_object uuid = service ExtrinsicObject objectType = Layer / featureType / CoverageOfferingBrief Service (WMS, WFS, WCS) uuid = classified_object ExtrinsicObject objectType = Layer / featureType / CoverageOfferingBrief ESG: ebRIM model of OGC Web Service

13 ExtrinsicOject objectType = Legend ExtrinsicOject objectType = LayerStyle Classification ExtrinsicObject objectType = Geometry Extents HasFootprint Externally Links Styles Service (WMS, WFS, WCS) Describes HasLegend ExtrinsicOject objectType = LayerStyle ExtrinsicOject objectType = Legend ExtrinsicObject objectType = Dataset Description (Metadata Document) Offers HasFootprint ExtrinsicObject objectType = Layer, or featureType, or CoverageOfferingBrief ExternalLink Extents ExternalLink Classification g.uuid = e.parent uuid = classified_object ESG: ebRIM model of OGC Web Service objects (WMS Layer, WFS FeatureType, WCS CoverageOffering)

14 ESG and CS/W interoperability ESG as CS/W server: ESG as CS/W server: – – Successful CS/W connections from Intergraph testbed client – Prototype CS/W connections from European Space Agency (ESA) client [http://eoportal.org] ESG as CS/W client: ESG as CS/W client: – Successful CS/W connections to GMU/CSISS ECHO connector Differences in ebRIM representations continue to be the main challenge Differences in ebRIM representations continue to be the main challenge – Conforming to CS/W is necessary but NOT sufficient for catalog interoperability

15 CS/W opportunities & challenges OGC CS/W interface definition is owned by no-one (consensus-based) OGC CS/W interface definition is owned by no-one (consensus-based) – Support by vendors, open source, etc. – Used across many different sectors of activity ebRIM is a promising common ground for catalogs ebRIM is a promising common ground for catalogs – Very flexible meta-model – Growing momentum in e-business Expect tools to manage the complexity Expect tools to manage the complexity ebRIM: not the answer BUT a good framework for expressing the answer ebRIM: not the answer BUT a good framework for expressing the answer

16 CS/W opportunities & challenges CS/W & ebRIM complexity / generality CS/W & ebRIM complexity / generality – Impedes wider implementation – Impedes wider consensus on profiles? Representing earth imagery in ebRIM: Representing earth imagery in ebRIM: – E.g., ESAs EO products profile (slow adoption so far) Lots of support for product ordering Lots of support for product ordering Little support for service binding Little support for service binding – No one ebRIM representation will fit everyone – Need an imagery counterpart to Dublin Core? NASA community could enhance catalog interoperability by defining one or more overlapping CS/W ebRIM representations NASA community could enhance catalog interoperability by defining one or more overlapping CS/W ebRIM representations


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