Centrum voor Geo-informatie

Metadata & clearinghouses

Madrid, 22 December 2004Joep Crompvoets

Spatial Data Infrastructures

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Overview Presentation

• Metadata– what is it ?– what are the standards ?– why is it difficult to organize ?

• A few remarks on Clearinghouses (Data catalogues)

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Metadata

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Dsal.dat

0 0 201 0 155 0 3510 0 4575 0 30. . .. . .

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Assignment

Write down 3 characteristics that you would use to describe, to someone else, a spatial dataset.

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Metadata and Clearinghouses

• Metadata (data about data)

• Metadata information system

• National and International collection of metadata and data IS (clearinghouse)

• Book description (data about books)

• Library information system

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Why describe spatial datasets?

Manage (storage and change) Search (content global ) Exchange (format ) Use (content details, Quality)

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Target groups

Personal (storage) Own organisation (storage and

content) Other organisations (content, format,

quality, contact person)

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Extent description

Target groups Functions

manage search exchange use Personal + + - - Own organisation ++ ++ ++ ++ Other organisation - +++ +++ +

++

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How to describe ?

• Personal standard• Organisational standard• (inter)national standards

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International standards

• America (FGDC)• Europe (CEN)• ISO (2003 world)

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Identification

Quality

Spatial reference Meta-data

reference

Classification

Administr.meta-data

Overview CEN meta-data

Datadefinition

CEN meta-data standardCEN meta-data standard

CEN meta-data

Extent

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NCGI data model NCGI data model

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ISO Standards and Technical Reports

ISO 6709:1983 Standard representation of latitude, longitude and altitude for geographic point locations

ISO 19101:2002 Geographic information — Reference model

ISO 19105:2000 Geographic information — Conformance and testing

ISO 19107:2003 Geographic information — Spatial schema

ISO 19108:2002 Geographic information — Temporal schema

ISO 19111:2003 Geographic information — Spatial referencing by coordinates

ISO 19113:2002 Geographic information — Quality principles

ISO 19115:2003 Geographic information — Metadata ISO/TR 19120:2001 Geographic information — Functional standards

ISO/TR 19121:2000 Geographic information — Imagery and gridded data

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ISO 19115

• 1 General information• 2 History• 3 Data identification• 4 Spatial information• 5 Distribution• 6 Meta-information reference

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Conclusions

• Describing spatial datasets with meta-data is essential to keep the data accessible in the future.

• For (inter)national exchange the use of a standard is a must.

• A problem with describing meta-data is that the personal requirements are less than the organisational requirements.

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Clearinghouses (Data catalogues)

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The name clearinghouse

• Banking• 1775 London

banker’s Clearinghouse

• Now national bank and IMF

• virtual market on the internet.

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What is a clearinghouse ?

• A virtual market on the internet for spatial data.

• A metadata information system.• With functions to search, to view,

to download and to pay for spatial data.

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Clearinghouse technical concepts

• Centralized (meta data in central database)

• Decentralized (meta data in local databases and a central query structure)

• Hybride system (part of the meta data central, part local)

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Conclusions

• Large amount of spatial data will become available (by the internet) for GIS.

• Spatial data infrastructures, clearinghouses and metadata play an important role in data delivery.

• Knowledge of quality, concepts of metadata is essential to turn data into information.