presentation charvat cerba

20
Ontology as Knowledge Base for Spatial Data Harmonization Otakar Cerba, Karel Charvat University of West Bohemia, Plzen, Czech Republic Help Service Remote Sensing, Benesov, Czech Republic 26.06.2012 1 INSPIRE 2012

Upload: karel-charvat

Post on 28-Aug-2014

750 views

Category:

Education


0 download

DESCRIPTION

 

TRANSCRIPT

Page 1: Presentation charvat cerba

Ontology as Knowledge Basefor Spatial Data Harmonization

Otakar Cerba, Karel Charvat

University of West Bohemia, Plzen, Czech RepublicHelp Service Remote Sensing, Benesov, Czech Republic

26.06.2012 1INSPIRE 2012

Page 2: Presentation charvat cerba

Objectives

Spatial data harmonization – basics Domain ontology – theory & essential principles Harmonization ontology – components Example of harmonization based on ontology Conclusion

26.06.2012 2INSPIRE 2012

Page 3: Presentation charvat cerba

Spatial data harmonization

Activity for elimination or reduction of heterogeneities of various properties of spatial data to support interoperability

The elimination of the aspects of spatial data heterogeneity cannot be based on a creation of some uniform rules and data models, because, there are too many subjects with individual requirements – formats, precision, reference systems, terminology...

The harmonization processes should be divided into small and simple substeps

26.06.2012 3INSPIRE 2012

Page 4: Presentation charvat cerba

Conditions of successful harmonization

Theoretical knowledge (domain, geomatic, IT...) Understandable user requirements Cooperation of experts Sequence of harmonization substeps Multi-level data description

26.06.2012 4INSPIRE 2012

Page 5: Presentation charvat cerba

Why to harmonize

To enable a sharing, combining and publishing of data To re-use existing sources To improve data quality To use web services and other automatic tools (SaaS) To keep data interoperability (it's cool!) To increase the number of stakeholders To meet legislation requirements All reasons

are strongly

interconnected

26.06.2012 5INSPIRE 2012

Page 6: Presentation charvat cerba

Ontology – Theory

To improve communication between all participating subjects (cartographers, users, IT experts, domain experts...)

...formal and formalized

explicit specification of

sharing conceptualizati

on … way how a human understands the world and how

it expresses

… exactly defined syntax… clearly

semantically defined concepts

… directly expressed

… precise list of terms

… suitable for re-use

26.06.2012 6INSPIRE 2012

Page 7: Presentation charvat cerba

Ontology – Fundamental components

Class (Concept) – particular parts of domain structured by is-a relation

Individual – particular parts of domain that cannot be divided

Property – detail description of specifics of classes or individuals; object & data type properties

Axiom – logical constructs between elements of ontology (e.g. closure axiom, cover axiom)

Annotation – metadata, description, explanation

26.06.2012 7INSPIRE 2012

Page 8: Presentation charvat cerba

Ontology: Classes & Properties

Classes Properties

26.06.2012 8INSPIRE 2012

Page 9: Presentation charvat cerba

Role of ontology in harmonization process

HeterogeneousData

HarmonizationTool(s)

HarmonizedData

DataDescription

Knowledge& Experience

Rules &Methods Ontology

To formalize

and process extra

information26.06.2012 9INSPIRE 2012

Page 10: Presentation charvat cerba

Data description in ontology

26.06.2012 10INSPIRE 2012

Page 11: Presentation charvat cerba

Proposal of harmonization substeps

After reasoning

Before reasoning

26.06.2012 11INSPIRE 2012

Page 12: Presentation charvat cerba

Inferred Ontology – Data Description

26.06.2012 12INSPIRE 2012

Page 13: Presentation charvat cerba

LU/LC Legend mapping ontology

26.06.2012 13INSPIRE 2012

Page 14: Presentation charvat cerba

LU/LC Legend mapping ontology – parameters

26.06.2012 14INSPIRE 2012

Page 15: Presentation charvat cerba

LU/LC Legend mapping ontology – example

Reasoning

Asserted (original)information

Inferred (new) information

Equivalentclasses

26.06.2012 15INSPIRE 2012

Page 16: Presentation charvat cerba

LU/LC Legend mapping ontology

26.06.2012 16INSPIRE 2012

Page 17: Presentation charvat cerba

Harmonization in ETL tool

Input file(CLC)

Replicationto moreoutputs

Transformationto new data

models

Changingattributevalues

Outputs(PELCOM etc.)26.06.2012 17INSPIRE 2012

Page 18: Presentation charvat cerba

Results of LULC data harmonization

CLC

PELCOM

PELCOMAfter manual final harmonization

26.06.2012 18INSPIRE 2012

Page 19: Presentation charvat cerba

Conclusion

Harmonization is not only technical process but also semantic...

It is necessary to consider a suitability of data sets from the view of Data completeness Data quality (depend for purposes of result) Semantics of the data sets and classification systems

Ontologies enable knowledge transfer and better communication (including information sharing)

26.06.2012 19INSPIRE 2012

Page 20: Presentation charvat cerba

Thank you for your attention and questions

[email protected]@ccss.cz

26.06.2012 20INSPIRE 2012