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Semantic search engine for

geographic data

Ontologies for urban development:

conceptual models for practitioners

Torino, 17 & 18/10/07

C. Pegoraro, M. Velluto

Direzione SISTEMI TERRITORIALI E AMBIENTALI

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Semantic search engine for geographic data

OUR DOMAIN: GEOGRAPHIC DATA PRODUCED BY LOCAL ADMINISTRATIONS

SITAD

is the instrument that allows finding and consulting data. It consists in two main

services:

3.

Search engine

. Data search in a metadata catalogue. Three ways:

Subjects – classified in a simple taxonomy

Simple – keywords

Advanced – combines keywords, subject and other info (geographic

coverage, data responsible, scale etc.)

Search results: metadata forms providing data related information, summarized in a

properties list according with Dublin Core standard (or ISO19115: more

detailed)

CSI Piedmont manages a great amount of geographic data: detailed territorial knowledge

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17/10/07 Pegoraro, Velluto Ontologies for urban development

Semantic search engine for geographic data

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Semantic search engine for geographic data

Search engine

. Data search in a metadata catalogue. Three ways:

Subjects – classified in a simple taxonomy

Simple – keywords

Advanced – combines keywords, subject and other info (geographic

coverage, data responsible, scale etc.)

Which is our

purpose

?

Add the fourth way to search data in SITAD:

ontology based

semantic search

Our purpose

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17/10/07 Pegoraro, Velluto Ontologies for urban development

Semantic search engine for geographic data

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Theoretical background: FOUR PILLARS for ontologies

Semantics

ONTOLOGY

Schema

Foundational

Ontology

CONCEPT

DICTIONARY

CONCEPTUAL

SCHEMA

META MODEL

Lexicon

+

+

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Semantic search engine for geographic data

Treccani Vocabulary of the Italian Language – textual

Treccani Vocabulary of the Italian Language – visual

Regulations on thematic extents: Italian Road Code,…

Technical & scientifical literature

CONCEPT

DICTIONARY

Lexicon

Semantics

Foundational

Ontology

CONCEPTUAL

SCHEMA

META MODEL

+

+

ONTOLOGY

Schema

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17/10/07 Pegoraro, Velluto Ontologies for urban development

Semantic search engine for geographic data

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Semantic search engine for geographic data

CONCEPT DICTIONARY Hints 2/3

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Semantic search engine for geographic data

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Semantic search engine for geographic data

CONCEPT

DICTIONARY

Lexicon

Semantics

Foundational

Ontology

CONCEPTUAL

SCHEMA

META MODEL

+

+

ONTOLOGY

Schema

Experimental Phase: REFERENCE MATERIAL 2/3

SITAD, Regione Piemonte

INTESA GIS, Italy, Centro Interregionale

EUROROADS, eContent

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17/10/07 Pegoraro, Velluto Ontologies for urban development

Semantic search engine for geographic data

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Semantic search engine for geographic data

CONCEPTUAL MODELLING Hints 2/3

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Semantic search engine for geographic data

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Semantic search engine for geographic data

CONCEPT

DICTIONARY

Lexicon

Semantics

Foundational

Ontology

CONCEPTUAL

SCHEMA

META MODEL

+

+

ONTOLOGY

Schema

Experimental Phase: REFERENCE MATERIAL 3/3

ISO Standards

JTC 1, Information Technology JTC 211, Geographic Information

other ISO thematic series

GEOUML from INTESA GIS specifications

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17/10/07 Pegoraro, Velluto Ontologies for urban development

Semantic search engine for geographic data

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Semantic search engine for geographic data

Allen

Egenhofer

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Semantic search engine for geographic data

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META MODEL Hints 3/3

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Semantic search engine for geographic data

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Semantic search engine for geographic data

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Semantic search engine for geographic data

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Semantic search engine for geographic data

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Semantic search engine for geographic data

Conceptual scheme (classes and relations)

High level

Conceptual scheme and objects

Low level

Certificated through national and international standards

Objects/instances

(metedata forms)

Certificated through Dublin Core or ISO

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17/10/07 Pegoraro, Velluto Ontologies for urban development

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To check the scheme: develop three parts of the ontology

Geometric ontology – referring to ISO TC 211 SERIES

A practical example

Thematic ontology – Civil Protection (referring to JRC ontology elaborated for the Regional Program for Risk Forecast and Prevention)

Thematic ontology – Viability (referring to Intesa GIS specifications)

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Semantic search engine for geographic data

Geometric ontology:

Describes the relations

connecting classes of

geometrical instances

Thematic ontology:

Describes the relations

connecting concepts in a

specific thematic discipline

(e.g.: viability or civil

protection)

How represent?

Two kinds of ontology

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17/10/07 Pegoraro, Velluto Ontologies for urban development

Semantic search engine for geographic data

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Geometric ontology:

•Classes: Contain geometric entities (e.g.: 2DSurfaces, 2DPoints, 3DComposite Curves etc)

•Relationships: hierarchical and topological (the 2Dsurfaces belong to the Surface class/

A 2Dsurface can adjoin to another or can contain it)

•Instances: Metedata forms (e.g. the form concerning the landslide areas is contained in the

2Dsurface class)

Thematic ontology:

•Classes: Contain conceptual entities (e.g.: In Civil Protection we have the Class ‘Risk’)

•Relationships: hierarchical and logical (e.g..: in Civil Protection, the Risk calculation requires the

defiition of other other concepts, such as Target, Impact Area, Risk source, etc)

•Instances: No real objects

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Semantic search engine for geographic data

Has subclass

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17/10/07 Pegoraro, Velluto Ontologies for urban development

Semantic search engine for geographic data

27 contains Is contained in contains Is contained in adjoining

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Semantic search engine for geographic data

Detail: hierarchical and topological relationships in geo ontology

contains

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17/10/07 Pegoraro, Velluto Ontologies for urban development

Semantic search engine for geographic data

29 Is necessary for

Requires

Internal to Internal to

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Semantic search engine for geographic data

Integrating the ontologies

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Semantic search engine for geographic data

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The consistency of the represented schemes

has been checked step by step using a Racer

Pro reasoner

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Semantic search engine for geographic data

•Which elements

are required

for

Risk

calculation

in

Civil Protection

?

•Which data (available in SITAD)

have

interest

in

Civil Protection

and

are

necessary

for

Risk Calculation

?

•Which data (available in SITAD) can

possibly

represent

Impact Areas

?

•What does a

Transport Network

Conlusions: semantic benefits

We can give answers to some complex questions…

•Impact Areas, Targets, Risk sources

and

Resources

•Transport Network

and

Landslides

Areas

•Every data

contained in

Surface

Class

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17/10/07 Pegoraro, Velluto Ontologies for urban development

Semantic search engine for geographic data

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Accomplish

the representation of geographic ontology scheme

(referring to ISO standard)

Aquire

thematic ontologies, referring to International or national

standards (translate available UML schemes in OWL)

Complete

the information from metadata forms through semantic and

lexicon standard sources.

References

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