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Intuitive, OGC-Conformant Search for Spatial and Non-Spatial Data in a Web-Based Information. Content. The context : WISDOM - W ater-related I nformation S ystem for the sustainable D evelopment o f the M ekong D elta , Vietnam Metadata : What it looks like Data search in WISDOM
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Intuitive, OGC-Conformant Search for Spatial and Non-Spatial Data in a Web-Based Information
Content • The context: WISDOM - Water-relatedInformationSystem forthesustainableDevelopmentoftheMekongDelta, Vietnam • Metadata: Whatitlookslike • Data search in WISDOM • Data searchandMetadata • Outlook
WISDOM System http://wisdom.eoc.dlr.de/Elvis
WISDOM System: Content in terms of topics Basin characteristics EO based Monitoring Analyses of Legal System Water Quality, Pollution Mekong Information System Institutional Mapping Water quantity, demand, reliability Training, CB Climate Change and Vulnerability Analyses Socio Economic Changes Landuse Change Slide 4
WISDOM System: Content in terms of data types Raster data Statistical data Vector data Mekong Information System in-situ sensor observations PDF documents
WISDOM System: Wrap up • Vastamountofdata • Different datatypes in onesystem • Different semanticsofdata Howto find appropriatedatawithintheinformationsystem? Weuse OGC compliantmetadatatodescribeeverydataset, beitgeographicor not!
Need for Metadata: OGC • The Open Geospatial Consortium (OGC) is an international standardization organization • Definition of standards for geospatial content and services, GIS data processing and data sharing Catalogue Service for the Web (CSW) as interface description that uses ISO 19139 to make metadata accessible on the World Wide Web
Need for Metadata: what is the content of metadata? Which region does it cover? Which projection? Which topic? ? Who is the point of contact? How was it produced? What about quality? Which time does it cover? Who provided the metadata? Metadata provide answers to these questions!
Need for Metadata: how does metadata look like? • ISO 19115:2003 and ISO 19139: The standards for metadata descriptions of geodata content for metadata • The metadata are structured as XML
Need for Metadata: WISDOM Profile • Discussion in project, whatinformationisneededasMetadata • Definition ofthesaurustocategorizedata, such asInfrastructure, Hydrology Lengthyprocesstoagree upon sharedvocabulary! We all neededtospeakthe same language
Meta- data Meta- data Meta- data Need for Metadata: Search in WISDOM Search for Data WMS CSW XML data describe
Data search in WISDOM: how does it look like? • Nofreetextsearchtoavoidfrustration: homonyms, synonymsetc • Search databyapplyingfilter • Time Topic • Region Datatype Search databyapplyingfilter
Request: Intersection of bounding box information <ogc:Intersects> Metadata
Data Search and Metadata: Keywords in Metadata Keyword „Infrastructure“ written toMetadata English and Vietnamese
Data Search and Metadata: Search results Vector Data Statistics Document
Tools thatsupportthegenerationofmetadataforusers • Altova Formular Tool • Online Metadata Tool (Data Entry Protal) These ensurethatmetadata fit tosearchandsearchfitstometadata.
Outlook • This approach can be transferred to other systems, as we use standards! • BUT: semantics differ between systems! Therefore, existing thesauri like GEMET should be used when defining project wide vocabulary
Thank you for your attention! Malte.Ahrens@dlr.de