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SOCoPSOCoPIntroduction to Spatial Introduction to Spatial

Ontologies Ontologies

Spatial Ontology Community Spatial Ontology Community of Practiceof Practice

Maps and map visualizationFeatures and feature geometriesGeographic and spatial-temporal relationships

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TopicsTopics

Value of OntologiesValue of Ontologies SOCoP OverviewSOCoP Overview Introduction to OntologiesIntroduction to Ontologies Ontological ExampleOntological Example

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Benefits of Formal Ontologies for Benefits of Formal Ontologies for OrganizationsOrganizations

Drivers - Ontologies are important for the federal Drivers - Ontologies are important for the federal government, because they enable semantic government, because they enable semantic translation and support standardization efforts translation and support standardization efforts such as the Federal Enterprise Architecture and such as the Federal Enterprise Architecture and its information models:its information models:• organize informationorganize information• quality controlquality control• information discoveryinformation discovery• data repurposingdata repurposing• integration of data sourcesintegration of data sources• enable semantic webenable semantic web

• Spatial Ontology - an explicit, partial description or vocabulary of Spatial Ontology - an explicit, partial description or vocabulary of representations which people use in geospatial/spatial domainsrepresentations which people use in geospatial/spatial domains

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Spatial Ontology Community of Spatial Ontology Community of Practice (SOCoP) Practice (SOCoP)

The Spatial Ontology Community of Practice was The Spatial Ontology Community of Practice was officially begun in October of 2006officially begun in October of 2006

Purpose Purpose • SOCoP is chartered as a Community of Practice under the Best SOCoP is chartered as a Community of Practice under the Best

Practices Committee of the Federal CIO CouncilPractices Committee of the Federal CIO Council

RoleRole

• To foster collaboration among researchers, technologists & To foster collaboration among researchers, technologists & users of spatial knowledge representations and reasoning users of spatial knowledge representations and reasoning towards the development of spatial ontologies for use by all in towards the development of spatial ontologies for use by all in the Semantic Web. the Semantic Web.

• Support open collaboration and open standards for increased Support open collaboration and open standards for increased interoperability of spatial data across government interoperability of spatial data across government

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Spatial Ontology Community of Spatial Ontology Community of Practice (SOCoP) Practice (SOCoP)

Role (continued)Role (continued)

• Synchronize with Geospatial Profile of FEA and the Geospatial Synchronize with Geospatial Profile of FEA and the Geospatial LOB as well as across the entire spectrum of applicable LOB as well as across the entire spectrum of applicable geospatial standards (via W3C, ISO, OGC, etc.).geospatial standards (via W3C, ISO, OGC, etc.).

• Document best practices, and create opportunities to partner Document best practices, and create opportunities to partner with other cross domain and ontology CoP groups. with other cross domain and ontology CoP groups.

• Help inventory geospatial ontologies, develop an approach to Help inventory geospatial ontologies, develop an approach to institutionalizing and streamline the effort to support the institutionalizing and streamline the effort to support the development and management of ontologies across geospatial development and management of ontologies across geospatial lines of business both in and out of government lines of business both in and out of government

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Spatial Ontology Community of Spatial Ontology Community of Practice Practice

Current FocusCurrent Focus• Build membershipBuild membership• Conduct an Inventory of Spatial OntologiesConduct an Inventory of Spatial Ontologies• Establish relationships with other geospatial ontology and semantics Establish relationships with other geospatial ontology and semantics

activities such as OGC, W3C, and the Geospatial Intelligence Standards activities such as OGC, W3C, and the Geospatial Intelligence Standards Working GroupWorking Group

• Participate/Present at Conferences and WorkshopsParticipate/Present at Conferences and Workshops• Examine the potential for a pilot Examine the potential for a pilot

MembershipMembership• Membership in the SOCoP is open to interested partiesMembership in the SOCoP is open to interested parties

Co-Chairs:Co-Chairs: • Kevin Backe, Topographic Engineering Center, US Army Corps of Kevin Backe, Topographic Engineering Center, US Army Corps of

EngineersEngineers• John Moeller, Northrop Grumman Information TechnologyJohn Moeller, Northrop Grumman Information Technology

Executive SecretariatExecutive Secretariat::• Gary Berg-Cross, Engineering, Management and IntegrationGary Berg-Cross, Engineering, Management and Integration

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Spatial Ontology Community of Spatial Ontology Community of Practice Practice

Meetings:Meetings:• Regularly Scheduled meetings are every other month on the Regularly Scheduled meetings are every other month on the

44thth Thursday from 11:00 – 1:00 ET Thursday from 11:00 – 1:00 ET

For more information go to the SOCoP wiki at: For more information go to the SOCoP wiki at: http://www.visualknowledge.com/wiki/socop

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Introduction to OntologiesIntroduction to Ontologies: : What is an Ontology For?What is an Ontology For?

Ontologies are a primary focus of the development of the Ontologies are a primary focus of the development of the Semantic WebSemantic Web

Different systems, on the internet and other government Different systems, on the internet and other government networks, typically cannot “talk” to each other since they do networks, typically cannot “talk” to each other since they do not share a common understanding of the datanot share a common understanding of the data• Metadata tagging is especially important for iconic data which

are not proceesable like strings and digits. Ontologies provides semantics for such metadata annotations.

Thus ontologies support information systems by providing an Thus ontologies support information systems by providing an unambiguous representation of the concepts and unambiguous representation of the concepts and relationships used in a given problem area relationships used in a given problem area • The ontology must take human-understandable concepts and The ontology must take human-understandable concepts and

make them processable by information systemsmake them processable by information systems• A quality ontology should serve as a robust reference framework to A quality ontology should serve as a robust reference framework to

which information systems can point to proscribe the meaning of which information systems can point to proscribe the meaning of information used by a systeminformation used by a system

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What Makes up an Ontology?What Makes up an Ontology? An An ontologyontology is an explicit description, preferably in a is an explicit description, preferably in a

formal language, based on a conceptualization of a formal language, based on a conceptualization of a domain. An ontology usually is built on :domain. An ontology usually is built on :• Classes Classes

A class can be thought of as a A class can be thought of as a conceptconcept in the domain in the domain• a class of air-traffic objects (e.g. Commercial Airport)a class of air-traffic objects (e.g. Commercial Airport)

a class of regions (e.g. Mid-Atlantic) a class of regions (e.g. Mid-Atlantic) • A class includes a A class includes a collectioncollection of elements with similar properties of elements with similar properties

The Backbone of an Ontology is made up of Classes in a Class The Backbone of an Ontology is made up of Classes in a Class Hierarchy (a formal taxonomy)Hierarchy (a formal taxonomy)

• Properties & attributes of concepts (with descriptions)Properties & attributes of concepts (with descriptions)• Relationships between classes like subClass, intersection, Relationships between classes like subClass, intersection,

unionunion• Relationships between classes and properties like Relationships between classes and properties like

allValuesFrom, cardinalityallValuesFrom, cardinality

How is an ontology represented?How is an ontology represented?• It is expressed within a It is expressed within a

representational formalism representational formalism which provides some which provides some degree of formal degree of formal semantics to express the semantics to express the meaning of its assertionsmeaning of its assertions

E.g. relational model, UML, E.g. relational model, UML, frames, logics, RDFS, OWL….frames, logics, RDFS, OWL….

However, these differ in However, these differ in expressivityexpressivity

p(x) y

API

In RDFS, there is not much one can say about a part-of propertyIf OWL we can: Define the properties partOf and hasPart as inverses, Define allValuesFrom restriction on the property partOf for all classes of things that are parts to the classes of things they are parts of, Define allValuesFrom restriction for the inverse property hasPart,Make partOf or hasPart transitive.

See http://www.w3.org/2001/sw/BestPractices/OEP/SimplePartWhole/

What Demo Ontology Looks Like - Class What Demo Ontology Looks Like - Class Hierarchy and AssertionsHierarchy and Assertions

Airplane

air-trafficobject

Physical-Object

Airportfuel-truck

Non-mobile-

resource

mobile-resource

isa

isa

isa

isa isa

isa

Gate

isa

Airport

Runway

comprisesRunway

xsd:int

runwayLength

Lighting

comprises

isLitBy

•Represents the geospatial world from the perspective of the relevant domain•Incoming data is mapped to this ontology upon entering the knowledgebase•Quality measured as ability to represent concepts in a potential question•Derived from the vocabulary of the users in this area

Imply inheritance for properties over subclasses

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Demo GoalDemo Goal Provide a set of ontologies Provide a set of ontologies

• Domain OntologyDomain Ontology Airports and AirplanesAirports and Airplanes

• Base Geospatial OntologyBase Geospatial Ontology Geometries from GMLGeometries from GML

• Filter OntologyFilter Ontology Spatial RelationshipsSpatial Relationships

• Feature OntologiesFeature Ontologies AIXM, DAFIF, GazetteerAIXM, DAFIF, Gazetteer

These support:These support:• A user asking a query in the vocabulary of his or her own A user asking a query in the vocabulary of his or her own

perspectiveperspective• Automatic query decomposition to original data source conceptsAutomatic query decomposition to original data source concepts• Automatic discovery of appropriate data sourcesAutomatic discovery of appropriate data sources• Ultimately, geospatial data interoperability that is transparent and Ultimately, geospatial data interoperability that is transparent and

useful to the useruseful to the user• Use different ontologies to address the problem modularlyUse different ontologies to address the problem modularly

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Ontology ModularityOntology Modularity

Base Spatial OntologiesBase Spatial Ontologies• Describes fundamental conceptsDescribes fundamental concepts

Ontology of GeometriesOntology of Geometries Ontology of Spatial RelationshipsOntology of Spatial Relationships

• Topological, Euclidean, Network basedTopological, Euclidean, Network based Spatial Domain OntologiesSpatial Domain Ontologies

• Describes concepts specific to a domainDescribes concepts specific to a domain HydrologyHydrology Disaster ReliefDisaster Relief Air Defense Air Defense Development and testing of these ontologies was done as Development and testing of these ontologies was done as

part of the OGC Interoperability Experiment on Geospatial part of the OGC Interoperability Experiment on Geospatial Semantic WebSemantic Web

• We used several OGC standards as starting material for We used several OGC standards as starting material for the ontologies.the ontologies.

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Sample “Logistic” QuerySample “Logistic” QueryWhat airports within 50000 meters of Saint Louis can support a C5?What airports within 50000 meters of Saint Louis can support a C5?

• Data needs to come from multiple sources!Data needs to come from multiple sources!

Aero Feature or Geo Feature?

Statutory or Nautical?Straight-line or driving?Coordinate system?

Feature property or non-spatial information?

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Geospatial Ontology UsageGeospatial Ontology Usage

Domain Ontology

WebFeature Service

KnowledgeBase

GeospatialFilter

OntologyBase

Geospatial Ontology

(Derived fromGML)

Feature Data Source

Ontology

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Base Geospatial OntologyBase Geospatial Ontology Foundation for all other geospatial related ontologiesFoundation for all other geospatial related ontologies Analogous to (and very likely derived from) GML and the Analogous to (and very likely derived from) GML and the

related abstract typesrelated abstract types Will need to evolve over time; a rich ontology with the Will need to evolve over time; a rich ontology with the

coverage of GML cannot be created overnightcoverage of GML cannot be created overnight

Geometry

LineStringPolygon Point

Spatial Region

Centroid

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Our Demo Domain OntologyOur Demo Domain Ontology

Airplane

air-trafficobject

Physical-Object

Airportfuel-truck

Non-mobile-

resource

mobile-resource

isa

isa

isa

isa isa

isa

Gate

isa

Airport

Runway

comprisesRunway

xsd:int

runwayLength

Lighting

comprises

isLitBy

•Represents the geospatial world from the perspective of the relevant domain•Incoming data is mapped to this ontology upon entering the knowledgebase•Quality measured as ability to represent concepts in a potential question•Derived from the vocabulary of the users in this area

NavAid ILS…Uses

DynamicEntity

isa

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Feature Data Source OntologyFeature Data Source Ontology Represents concepts needed to describe features Represents concepts needed to describe features

returned from a feature serverreturned from a feature server Extends the concepts of the base geospatial Extends the concepts of the base geospatial

ontology as related to the domain of the web ontology as related to the domain of the web feature serverfeature server

Data Source Ontologies Derived from:Data Source Ontologies Derived from:• DAFIFDAFIF

Aeronautical data – US standardAeronautical data – US standard Simple ontology mirrors DAFIF schemaSimple ontology mirrors DAFIF schema

• AIXMAIXM Aeronautical data – US/European standardAeronautical data – US/European standard Ontology mirrors XML schemaOntology mirrors XML schema

• GazetteerGazetteer City locationsCity locations

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Geospatial Filter OntologyGeospatial Filter Ontology Ontology to represent geospatial relationshipsOntology to represent geospatial relationships Used by the WFS client to represent queriesUsed by the WFS client to represent queries Used by the WFS to advertise available filters and Used by the WFS to advertise available filters and

accept filter queriesaccept filter queries

Overlaps

Geometry

operand

Geometry

operand

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Ontologies Together as a QueryOntologies Together as a Query

C5CapableAirport

50000mradius

DWithin

satisfiesFilter

City

referenceGeometry

PropertyIsLikesatisfiesFilter

“NAME”property

“Saint Louis”literal

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Ontologies Together in ActionOntologies Together in Action

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Future DirectionsFuture Directions

Investigate/develop spatial Investigate/develop spatial representationsrepresentations

Develop ontology alignment tools Develop ontology alignment tools and techniquesand techniques

Prototype spatial semantic Prototype spatial semantic knowledgebaseknowledgebase

Semantic service oriented Semantic service oriented architecturesarchitectures

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Recap: Rationale for Ontologies: Recap: Rationale for Ontologies: whywhy they matter they matter

Quality ontologies serve to resolve semantic differences between Quality ontologies serve to resolve semantic differences between disparate “informational concepts” such as business definitions disparate “informational concepts” such as business definitions and metadata descriptions, and metadata descriptions, • e.g. “Gauge Height = Stage = Stream Gauge”, e.g. “Gauge Height = Stage = Stream Gauge”, • They do this by representing intended meaning in a formalism such They do this by representing intended meaning in a formalism such

as OWL (Web Ontology Language). as OWL (Web Ontology Language).

Build the framework for Semantic Service Oriented Architectures Build the framework for Semantic Service Oriented Architectures (SOA) such as supports standard messaging: (SOA) such as supports standard messaging: • Geospatial ontologies allow the creation of Controlled Vocabulary for Geospatial ontologies allow the creation of Controlled Vocabulary for

purposes such as navigation, discovery of geo-spatial data, etc.purposes such as navigation, discovery of geo-spatial data, etc.• Formal ontologies provide a means for communication between or Formal ontologies provide a means for communication between or

among people, organizations, and/or software systems through among people, organizations, and/or software systems through standardization and consistencystandardization and consistency

Formal ontologies can be designed modularly with some general Formal ontologies can be designed modularly with some general modules for use across systems or application areas. modules for use across systems or application areas. • In this way, ontologies can be exchanged among heterogeneous In this way, ontologies can be exchanged among heterogeneous

systems that may also use them differently.systems that may also use them differently.