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OPeNDAP/ECHO DemoIntegrating and Chaining services
September, 2006CEOS WGISS 22Annapolis, MD
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Demo Background
OPeNDAP• Software framework which supports simple access and analysis of data• Clients don’t have spatial/temporal search capability for data discovery
ECHO• Metadata and Service Registries• Provides extensive product search capabilities for discovery
Integration• Can OPeNDAP enabled software take advantage of ECHO search?• Can existing solutions like OPeNDAP work with ECHO? How hard is it?
History• Initial discussions between OPeNDAP and ECHO teams occurred in late
October and November. • First phase prototype defined in November 2005, prototype pieces built in
December 2005, and demonstrated in Jan 2006 at the ESIP Federation meeting.
Current state• Next step prototype: Search of ECHO, using ECHO web services, access &
analysis of data all within Matlab analysis environment . • Prototype pieces built in spring 2006.• Modified Matlab GUI-ette expected to be used operationally in late 2006.
Leveraging ECHO and Web Services to expand value of existing services
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Demo Scenario
Science Scenario• Scientist wants to investigate how rainfall affects
sea surface temperature and validate his model for sea surface temperature with remote observations.
Presentation• Science View• Technology View
Supporting real science scenario – validating models
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Workstation
HyCOM Data Server(Miami, FL)
ECHO Data Catalog
ECHO Service Registry
ECHO Test Bed
MetadataIngest
Spatial/TemporalQuery
OPeNDAPQuery
Service
SOAP Invocation
GSFC(TRMM) JPL
(MODISTerra)
Demo Walk Through
Javaclass
Data Visualization and Analysis
Spatial/Temporal Query Parameters
OPeNDAP URLs, selected metadataMatlabscripts
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What Made the Demo Work?
We are using the work of an ongoing REASON project that provides OPeNDAP access to data pools at the GES DAAC and the PO.DAAC
Components• OPeNDAP Servers which provide access to data in GES DAAC and PO.DAAC
data pools.• ECHO Testbed (Version 8.0) populated with metadata from GES DAAC
data pool and the PO.DAAC• OPeNDAPQueryService returns the metadata results of query. Provides
search by dataset, time, space, and keyword. Results have OPeNDAP URLs for online access.
• Java Class reusable class which invokes the OPeNDAPQueryService.• Matlab “Gui-ette” presents user interaction, calls the java class, accesses
the data via OPENDAP and visualizes the data for analysis
Interoperability• ECHO Testbed (Version 8.0) has a collection-level PSA referencing the
OPeNDAP server. Granules OnlineAccessURL attribute populated with Data Pool URL.
• OPeNDAPQueryService published in the ECHO Services registry, classified in DataSet Taxonomy for demo collections
• Parallel Service & Metadata Registries in ECHO make the linkage workIntegrating existing solutions to make science easier
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Total Effort for Prototype
OPeNDAPQueryService• Development (extending previous demo’s service)• ECHO Services Registry – new service published
ECHO Testbed• Version 8.0.3• Populated with metadata
• GES DAAC data pool (data of interest for demo)• PO.DAAC• Added Collection-level Product Specific Attribute for OPeNDAPServer
Java class• Invoke OPeNDAPQueryService through SOAP
• Submit Query• Traverse Results - access the OPeNDAP URL information and granule ID information
• Spatial/Temporal fields converted for Matlab usageMatlab Gui-ette• Modified existing tool• Call java class• Additional script to access and analyze the new satellite data to select data to compare
with the model dataEffort• Extending January demo (direct Matlab access)• Couple months of total effort
New and innovative solutions with minimal effort
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Reflections
ECHO Lessons Learned• API Specifications include unspoken and implied
assumptions•Did a great job of specifying the external service•Still assumed the sorting was ok
• User-specified sorting of results (9.0 requirement)• Value of embedding access mechanisms
OPeNDAP Lessons Learned• Value of web services
•Using wsdl to build clients was very easy using standard development tools
•Generalized approach is portable and reusable
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ECHO Services & Metadata Registries Equal Middleware
ECHO provides Service-Oriented middleware support for• Enabling…• Catalog Services - metadata search• Services Registry - service definitions and access using
standardsExisting systems can build on top of ECHO• Leveraging existing investments• Expanding the value by integrating into a Service Oriented
EnterpriseECHO Testbed• Will continue to be available for the community and
welcomes additional participants!Non-programmer development of analysis scripts• Support beyond Matlab is available
DAP services will be converted to Web Services• Published in ECHO Service Registry
