Smart Maps and Dumb Questions:A Geospatial Semantic Web Interoperability Experiment

Joshua LiebermanTraverse Technologies, Inc. &

Northrop Grumman Information Technology / TASCjlieberman@traversetechnologies.com

© 2004 Traverse Technologies Inc.

Background Geospatial Semantic Web: Use of Semantic Web technologies to discover

and reason on geospatial information (UCGIS, Egonhofer, Sheth, etc.) GSW broad research activity sponsored by National Geospatial Intelligence

Agency (NGA), undertaken by a number of investigators Interoperability experiment: an Open Geospatial Consortium(OGC) -

sanctioned member collaboration to test or refine OGC specifications This “GSW IE”: activity proposed by NGA, NGIT/TASC, and BBN to test and

refine OGC(+) specifications within a scenario for geospatial query with formal semantics: Web Feature Service (WFS) and Filter Encoding (FE) Geographic Markup Language (GML) ISO 19115 / 19119 / 1910n / FGDC feature metadata (ISO)

Other initial participants: SCO, Jaume I, Muenster, Galdos, GMU, …

© 2004 Traverse Technologies Inc.

Drilling Down: The Geospatial part

Maps and map visualization Features and feature geometries Geographic and other relationships

The Web part Distributed data - “maintain locally / access globally” Shared services, loosely or tightly coupled to geodata Interoperability between technologies, vendors, architectures

The Semantic part Interoperability between communities and domains Softer software Automated reasoning and inference

© 2004 Traverse Technologies Inc.

Goals of this experiment

Exercise current semantic technology in a geospatial domain End-to-end geospatial semantic query Utilize multiple ontologies for Geointel operations Develop OGC service descriptions with formal semantics

(OWL-S for WFS) Develop and test Semantic Web Services interface / role for

OGC services Enhance interoperability in a distributed, heterogeneous world

© 2004 Traverse Technologies Inc.

The Web Changes Everything

Global communities for local geography Distributed information networks Premium on interoperability The GIS dialtone Maintain locally, access globally Currency is the currency (non-GIS) barbarians are at the (GIS) gate

© 2004 Traverse Technologies Inc.

Role of interoperability

Focuses on sustained operability - today and the next day Permits separation of concerns Supports information portability Allows component interchangeability Contributes to transparency, testability, and trust Layers of interoperability build on one another Stable syntax promotes shared semantics / understanding Standards are necessary but not sufficient for interoperability

© 2004 Traverse Technologies Inc.

Interoperability Stack

Meaning - ? (OWL, RDF, MDL, …)

Vocabulary – UML, XML Schema, OWS

Encoding - ASCII, UTF-8, XML

Control – TCP, HTTP, WAP

Signal – Internet Protocol, DNS

Transport – Ethernet, WiFi, GPRS

Medium – Physical Connection

Increasing interoperability

Human-centric

Machine-centric

© 2004 Traverse Technologies Inc.

Geospatial Reasoning: 2-D and Beyond Coordinate relationships

Scale significance Coordinate reference systems

Topological relationships Network Overlay

Spatial inference Proximity Continuity Representation Dimensionality Temporality

© 2004 Traverse Technologies Inc.

“Typical” GeoIntel Query:

“Which airfields within 500 miles of Kandahar support C5A aircraft?”

Aero Feature or Geo Feature?

Buffer or proximity?

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

Centroid or outline?

What does this mean?

Feature property or non-spatial information?

© 2004 Traverse Technologies Inc.

Sequence of Experiments

Link Ontologies into Knowledgebase

Generate and Visualize OWS (WFS) Queries

Request Remote Service Descriptions

Process Queries Through Knowledgebase

Compose Queries and Query Templates

Generate and Distribute Sub-queries

Identify and Build Ontologies for Geospatial / GeoIntel Domains

© 2004 Traverse Technologies Inc.

GSW Ontology Components

GeoIntelProblem Domain

Ontology

Base Geospatial Ontology

NGA Feature Ontology

OGC ServicesOntology

Other Base Ontologies

© 2004 Traverse Technologies Inc.

Ontology Construction Set

ECDMEntities & Relates

ECDM Business Rules

ELDM Entities & Attributes

GEOINT Vocabulary

Geospatial Schemas (OGC, ISO)

GeoIntelProblem Domain

OntologyBase Geospatial Ontology

NGA Feature Ontology

Initial Translation + Iterative Optimization

© 2004 Traverse Technologies Inc.

(Joy of) Ontology Observations ECDM is not an ontology but a “raw material” to be mined for ontology

concepts and initial relationships. LDM (Logical Data Model) attributes and ECDM Business Rules are needed

to “enrich” the resulting ontology. ECDM Business rules may be more completely captured in SWRL (Semantic

Web Rules Language) statements within the ontologies GEOINT business rules (possibly abstracted from classified sources) are

needed for building the problem domain ontology (GPDO). GPDO may also provide connections between the ECDM-type feature

ontology and Web Feature Service ontology (c.f. present OWL-S limitations regarding service content).

Analysis of successful / unsuccessful test queries will be used to iteratively improve the working ontologies.

© 2004 Traverse Technologies Inc.

Initial ECDM Selections for Experiment

AirportAirport

RunwayRunway

TaxiwayTaxiwayApronApron

ObstructionObstructionThresholdThreshold

RouteRoute

PlanePlane

ItineraryItinerary

RepairRepair

WeatherWeather

Nav AidsNav AidsServiceService

FuelFuel

LightingLighting

VORVOR

NDBNDBILSILS

MLSMLS

TACANTACAN

© 2004 Traverse Technologies Inc.

Model Query Sequence

Question

Template

Query Rules & Artifacts

Query Rules & Artifacts

Knowledge Base

Reasoning & Inference

Domain Ontology

Ontologies

RemoteWFS

WFS Get

Feature

Local Ontologies

Visualizer

Map

KnowledgeServer

Knowledge Server

Sub-query

Service Response

Query ClientVisualization

Client

© 2004 Traverse Technologies Inc.

GEOINT Query Has…

Concepts/Relationships, e.g. OWL ontology elements

Rules, e.g. RuleML (SWRL) Completion Criteria, e.g. SeRQL query

elements (precondition) Inference-based

knowledge refinement

Question

Template

Query Rules

Query Rules

Domain Ontology

Query Client

© 2004 Traverse Technologies Inc.

(Some) Technology Options

ArcGIS

Semantic Feature Visualizer Plugin

Semantic Query Plugin

DbSAIL WebSAIL

GeoSAIL

Query Layer (SeRQL)

HTTP API

Sesame Processing Framework

DamlDBWFS

JTS

Templates

MemoryInferenceSAIL

REP API GRAPH API

© 2004 Traverse Technologies Inc.

OWL-S Service Description Components and QuestionsType of Service

Themes of Content

Provider / business terms

Content Description

Service Bindings / Messages

Bound Parameters

Service Quality

Smart Service Consumption

Service Composition

Service Profile

Service Grounding

Service Model

Feature Schema

Content Domain

Feature Individuals

?

© 2004 Traverse Technologies Inc.

Proposed (Interoperability) ExperimentsExperiment #1: Construct a feature dataset ontology (for the GEOINT domain) using OWL in order to describe 5-6 sample feature collections. Experiment #2: Construct an OWS service description ontology using OWL-S in order to describe WFS services.

Experiment #3: Translate realistic GEOINT request into a semantic query language encoding (requires additional geospatial and problem domain ontologies).

Experiment #4: Perform an end-to-end geospatial semantic query in a non-distributed environment using the results of Experiment #1-Experiment #3; the result of this query process will be WFS service requests for information which satisfies the query.

Experiment #5: Implement and test an OWS capabilities type and/or interface which returns service / content descriptions such as in Experiment #1 and Experiment #2 from WFS service instances. Experiment #6: Perform an end-to-end geospatial semantic query as in Experiment #4 but involving remote requests for metadata as in Experiment #5.

© 2004 Traverse Technologies Inc.

This.Road_Ahead

More and further Geo-semantic Catalogs (c.f. OWS-3) Semantic Service-oriented Architectures Agent Façades Knowledge Services Fine-grained, dynamically combinable geoservices Your Problem Domain