Recent Advances in Geospatial Service Chaining Open Standards 2008 Composability within SOA Symposium April, 2008 Raj Singh, PhD OGC Director of Interoperability Programs

Agenda Background on OGC OGC Test beds and OWS-5, the workflow test bed Background on the domain problem – Conflation The added complexity of cross-organization interoperability The solution: OGC Web Services and BPEL workflow 2 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

OGC, the Organization

Everything happens somewhere – and “somewhen”! …it’s estimated that 80 to 90% of all data maintained or archived in databases has some geographic property! Can anyone think of an activity that does not have the properties of geographic location and time, or that impacts a location over time? 4 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

The Challenges Discovery: These data are distributed in tens of thousands of repositories Access: They will never, ever be put into massive centralized repositories Processing and fusion: These data typically must be processed in order to be useful for the end-user application Decision makers, policy makers, scientists, researchers, consumers, emergency response – all need access to the latest and best geo content and services – when and where they need it! 5 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

OGC Snapshot A not-for-profit, voluntary, consensus Standards Organization founded in 1994 To serve as a global forum for the development, promotion and harmonization of open and freely available geospatial standards Currently ~350 member organizations Twenty four adopted standards Four OGC Standards are now also ISO Standards 6 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

Alliance Partnerships Critical To Successful Standards Development and Implementation and others… 7 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

OGC’s Foundation Data Access Standards WMS: Web Mapping Service: web images of maps WFS: Web Feature Service: vector data WCS: Web Coverage Service: raster imagery and grids GML: Geography Markup Language: XML encoding of data SOS: Sensor Observation Service: real-time data CSW: Catalogue Service for the Web: geospatial search WPS: Web Processing Service: run a model/algorithm/process 8 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

But now we must combine them into processing and fusion services Source: Broadstroke 9 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

The OGC Interoperability Program & OWS-5

OGC’s Approach for Advancing Interoperability Interoperability Program (IP ) - a global, innovative, hands-on prototyping and testing program designed to accelerate interface development and validation, and bring interoperability to the market Specification Development Program –Consensus processes similar to other Industry consortia (World Wide Web Consortium, OMA, OMG, etc.). Outreach and Community Adoption Program – education and training, encourage take up of OGC specifications, business development, communications programs Rapid Interface Development Standards Setting Market Adoption 11 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

Testbeds Enhance Standards 12 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

Examples of Interoperable (Open) Geospatial Service Chaining

Why? Large data sets: up to terabytes Issues of provenance Organizational information management 14 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

Imagery Processing Workflow … Internet OGC Interfaces Service chaining creates value-added products from SWE Observations WCS = Web Coverage Service WCTS = Web Coordinate Transformation Service WPS = Web Processing Service SOS WCTSWPSWFS decision support client 15 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

Data Reduction Workflow Steven Keens, PCI 16 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

Use Case: workflow for geospatial data conflation

18 Conflation Use Case Conflation is the process of unifying multiple separate sources of data into one integrated all-encompassing result Conflation is a complex task with many variations and rules that guide the discovery and combination of features Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

Conflation Use Case Preserve geometry connectivity (vertical red to green, upper center right) Resolve potential overshoot issues (unique red feature, middle center right) Conflate attributes 19 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

20 Issues in Conflation Metadata Lineage: the origins of each feature must be retained Absolute Horizontal Accuracy: spatial accuracy relative to true location Feature Type: Feature description information Alignment: Spatial agreement among features Competition: choice of alternatives when determining common features Geometry: point, line, area (polygon) and other geometries Coordinate Specification: issues associated with potential differences Duplicate Features: duplication in coordinates and/or attribute values Schemas: differences in description of attributes, data type, units of measure, domain Feature Association full feature matching: association made on complete features only partial feature matching: only a subset of a feature associates to a feature in the other data set single feature matching: matched exclusively on a one-to-one basis, in whole or part multi-feature matching: any given feature in one source matches to several in the other Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

21 Families of Conflation Business Rules MatchingSimilarity Selection To find the same features and attributes Feature Types - Names and Codes Schema – attribution names, units, enumeration To match two or more features Geometry/location – accuracy and tolerance Attribute matching values, null/unknown attribute value Feature Type matching Geometry Type matching To select the Quality of the resultant features Quality preference rules Join/Merge attribute precedence and conversion of expected output All of the common Conflation Tools have some form of business rule definition and logic that is applicable to these families of rules. Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

22 Rules as Web Services Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

Workflow deployment strategy Idealized –Rules are web services –BPEL describes rules application –Client has a rule editor Pick rules from a GUI Build a BPEL workflow Actual –Rules are processes –BPEL describes calling a Web Processing Service –WPS is a web services wrapper for rules 23 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

Web Processing Service WPS WPS-client Web Processing Service GetCapabilitiesDescribeProcessExecute Algorithm Repository … … Algorithm 1 … … Data Handler A Data Handler Repository Communication over the web using HTTP 24 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

Deployment of Conflation Services – Ideal 25 Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

26 Deployment of Conflation Services – Actual BPEL Engine WPS WFS Radius Studio™ Source data Template Rules (xml) Results (xml) Parameterised Rule (xml) Result Data Client GML SOAP request SOAP response WFS GML 2 HTTP Get/Post SOAP Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved

27 Lessons Learned BPEL + OGC Web Services works Initial hurdles were hard, so we only have simple workflows –SOAP-WSDL for all OGC services –SOA for rules Future work items –More complex workflows –More detailed WPSes Helping the World to Communicate Geographically Copyright © 2008, Open Geospatial Consortium, Inc., All Rights Reserved