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

OGC Catalog Service for the Web OGC Catalog Service for the Web (CS/W): experience in NASA(CS/W): experience in NASA

John D. Evans, Ph.D.John D. Evans, Ph.D.john.evans@nasa.govjohn.evans@nasa.gov

NASA Geosciences Interoperability Office (GIO)NASA Geosciences Interoperability Office (GIO)Earth Science Applications DivisionEarth Science Applications Division

-/- Global Science-/- Global Science & Technology, Inc.& Technology, Inc.

Goddard Space Flight Center, Greenbelt, MDGoddard Space Flight Center, Greenbelt, MD

Introduction & overviewIntroduction & overview

● OGC CS/W specification: Spring 2004OGC CS/W specification: Spring 2004– (After many iterations)(After many iterations)

● OGC ebRIM profile: Fall 2005OGC ebRIM profile: Fall 2005● NASA experimenting with CS/W since Fall 2004NASA experimenting with CS/W since Fall 2004● Two implementations in particular:Two implementations in particular:

– ECHO CS/W connectorECHO CS/W connector (Center for Spatial Information (Center for Spatial Information Science & Systems [CSISS], George Mason University)Science & Systems [CSISS], George Mason University)

– Earth Science GatewayEarth Science Gateway (NASA Geosciences (NASA Geosciences Interoperability Office [GIO] & Compusult Ltd.)Interoperability Office [GIO] & Compusult Ltd.)

● Implementation experienceImplementation experience– Insights, opportunities, and challengesInsights, opportunities, and challenges

GMU / CSISS experience with CS/WGMU / CSISS experience with CS/W

● Bird’s eye viewBird’s eye view

- From Bai, Y., et al., 2007: Towards a Geospatial Catalogue Federation Service, Photogrammetric Engineering & Remote Sensing 73 (6), pp. 699-708

GMU / CSISS experience with CS/WGMU / CSISS experience with CS/W

● Inside the Catalogue Federation ServiceInside the Catalogue Federation Service

- From Bai, Y., et al., 2007: Towards a Geospatial Catalogue Federation Service, Photogrammetric Engineering & Remote Sensing 73 (6), pp. 699-708

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/WGMU / 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

GMU / CSISS: CS/W bridge to ECHOGMU / CSISS: CS/W bridge to ECHO

● http://laits.gmu.edu:8099/ECHO9CSW2/discoveryhttp://laits.gmu.edu:8099/ECHO9CSW2/discovery

● Connects to the full, operational ECHOConnects to the full, operational ECHO● Partial ECHO–ebRIM mapping. Emphasis:Partial ECHO–ebRIM mapping. Emphasis:

– CS/W core queryables (Dublin Core)CS/W core queryables (Dublin Core)– Granules (not Collections)Granules (not Collections)

● Performance issues:Performance issues:– ECHO not fully optimized for granule-level searchECHO not fully optimized for granule-level search– ECHO 8 responds to most queries from CS/W ECHO 8 responds to most queries from CS/W

connector in under 2 minutes (used to be worse)connector in under 2 minutes (used to be worse)– ECHO 9 may further improve query performanceECHO 9 may further improve query performance

● Multiplicity of schemas poses add’l challengesMultiplicity of schemas poses add’l challenges– CS/W used as a “hub” for several different catalogsCS/W used as a “hub” for several different catalogs

NASA / GIO Earth Science Gateway (ESG)NASA / GIO Earth Science Gateway (ESG)

Earth Science Gateway (ESG)Earth Science Gateway (ESG)Service ManagerService Manager

OGCWMS

Servers

ServiceManager

Service RegistryDatabase (Oracle)

WebPublishing

Client

OGCWFS

Servers

OGCWCS

Servers

ExternalApplications/Clients

OGC CSW Requests - GetCapabilities (1) - GetRecords (2)

OGC CSW Transactions (3) - Insert - Update - Delete

OGC Repository Extensions - GetRepositoryItem (4) - PutRepositoryItem (5)

Capabilities XMLDocument (1)

Transaction Status (3)

SearchResults (2)

RepositoryItem (4)

Repository Status (3)

OGCWMS

Servers

ServiceManager

Service RegistryDatabase (Oracle)

WebPublishing

Client

OGCWFS

Servers

OGCWCS

Servers

ExternalApplications/Clients

OGC CSW Requests - GetCapabilities (1) - GetRecords (2)

OGC CSW Transactions (3) - Insert - Update - Delete

OGC Repository Extensions - GetRepositoryItem (4) - PutRepositoryItem (5)

Capabilities XMLDocument (1)

Transaction Status (3)

SearchResults (2)

RepositoryItem (4)

Repository Status (3)

Earth Science Gateway (ESG)Earth Science Gateway (ESG)Service ManagerService Manager

● ESG portal uses CS/W internally for all ESG portal uses CS/W internally for all catalog accesscatalog access– SearchSearch

– PublishPublish

– HarvestHarvest

● Public interface available for other CS/W clientsPublic interface available for other CS/W clients● Simple HTML client can query other CS/W serversSimple HTML client can query other CS/W servers

ESG in OGC Web Services Testbed 3ESG in OGC Web Services Testbed 3

● Successful connections from a Refractions Successful connections from a Refractions Research CS/W client (Nov. 2005)Research CS/W client (Nov. 2005)

● Key challenge: reconciling different ebRIM Key challenge: reconciling different ebRIM representationsrepresentations– E.g., WMS Layer Extrinsic Object: is its ObjectType E.g., WMS Layer Extrinsic Object: is its ObjectType

““LayerLayer””? ? ““WMS_LayerWMS_Layer””? or ? or ““Data_SetData_Set””??– A guessing game; create equivalencies to fit queries A guessing game; create equivalencies to fit queries

coming from different clientscoming from different clients– Changing an ebRIM type name can be a headacheChanging an ebRIM type name can be a headache

● Another challenge: maintaining performanceAnother challenge: maintaining performance– Query response slowed a lot at 100k-200k records.Query response slowed a lot at 100k-200k records.– Server-side workarounds: temp tables; caching; Server-side workarounds: temp tables; caching;

returning summaries rather than full recordsreturning summaries rather than full records

ESG in OGC Web Services Testbed 4ESG in OGC Web Services Testbed 4

UAV

EO-1

Service Binding

Classification

ExtrinsicObjectobjectType =

Geometry

ExtrinsicObjectobjectType =

Context Document(WMS only)

HasFootprint

Offers

HasContext

ServiceBinding

Extents

User

OffersService

ExtrinsicObjectobjectType =

Dataset Description (Metadata Document)

HasFootprint

Describes

Classification

Classification

uuid = parent

uuid = classified_object

uuid = service

ExtrinsicObjectobjectType =

Layer / featureType /CoverageOfferingBrief

Service(WMS, WFS, WCS)

uuid = classified_object

ExtrinsicObjectobjectType =

Layer / featureType /CoverageOfferingBrief

ESG: ebRIM model of OGC Web ServiceESG: ebRIM model of OGC Web Service

ExtrinsicOjectobjectType = Legend

ExtrinsicOjectobjectType

= LayerStyle

Classification

ExtrinsicObjectobjectType = Geometry

Extents HasFootprint

Externally Links

Styles

Service(WMS, WFS, WCS)

Describes

HasLegendExtrinsicOjectobjectType =

LayerStyle

ExtrinsicOjectobjectType = Legend

ExtrinsicObjectobjectType =

Dataset Description (Metadata Document)

Offers

HasFootprint

ExtrinsicObjectobjectType = Layer, orfeatureType, orCoverageOfferingBriefExternalLink

Extents

ExternalLink

Classification

g.uuid = e.parent

uuid = classified_object

ESG: ebRIM model of OGC Web Service objectsESG: ebRIM model of OGC Web Service objects(WMS Layer, WFS FeatureType, WCS CoverageOffering)(WMS Layer, WFS FeatureType, WCS CoverageOffering)

ESG and CS/W interoperabilityESG and CS/W interoperability

● ESG as CS/W server:ESG as CS/W server:– http://esg.gsfc.nasa.gov/wes/serviceManagerCSW/cswhttp://esg.gsfc.nasa.gov/wes/serviceManagerCSW/csw – Successful CS/W connections from Successful CS/W connections from

Intergraph testbed client Intergraph testbed client – Prototype CS/W connections from European Space Prototype CS/W connections from European Space

Agency (ESA) client Agency (ESA) client [[http://eoportal.org]http://eoportal.org]● ESG as CS/W client:ESG as CS/W client:

– Successful CS/W connections to GMU/CSISS ECHO Successful CS/W connections to GMU/CSISS ECHO connectorconnector

● Differences in ebRIM representations continue to Differences in ebRIM representations continue to be the main challengebe the main challenge– Conforming to CS/W is necessary but NOT sufficient Conforming to CS/W is necessary but NOT sufficient

for catalog interoperabilityfor catalog interoperability

CS/W opportunities & challengesCS/W opportunities & challenges

● OGC CS/W interface definition is owned by OGC CS/W interface definition is owned by no-one (consensus-based)no-one (consensus-based)– Support by vendors, open source, etc.Support by vendors, open source, etc.

– Used across many different sectors of activityUsed across many different sectors of activity

● ebRIM is a promising “common ground” for ebRIM is a promising “common ground” for catalogscatalogs– Very flexible meta-modelVery flexible meta-model

– Growing momentum in e-businessGrowing momentum in e-business● Expect tools to manage the complexityExpect tools to manage the complexity

● ebRIM: not the answer BUT a good framework ebRIM: not the answer BUT a good framework for expressing the answerfor expressing the answer

CS/W opportunities & challengesCS/W opportunities & challenges

● CS/W & ebRIM complexity / generalityCS/W & ebRIM complexity / generality– Impedes wider implementationImpedes wider implementation

– Impedes wider consensus on profiles?Impedes wider consensus on profiles?

● Representing earth imagery in ebRIM:Representing earth imagery in ebRIM:– E.g., ESA’s EO products profile (slow adoption so far)E.g., ESA’s EO products profile (slow adoption so far)

● Lots of support for product orderingLots of support for product ordering● Little support for service bindingLittle support for service binding

– No one ebRIM representation will fit everyoneNo one ebRIM representation will fit everyone

– Need an imagery counterpart to Dublin Core?Need an imagery counterpart to Dublin Core?

● NASA community could enhance catalog NASA community could enhance catalog interoperability by defining one or more interoperability by defining one or more overlapping CS/W ebRIM representationsoverlapping CS/W ebRIM representations