intuitive, ogc conformant search for spatial and non-spatial data in a web-based information system...
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Intuitive, OGC conformant search for spatial and non-spatial data in a web-based information system > Malte Ahrens > 2013-04-22
Intuitive, OGC-Conformant Search for Spatial and Non-Spatial Data in a
Web-Based Information
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Content
The context: WISDOM - Water-related Information System for the sustainable Development of the Mekong Delta, Vietnam
Metadata: What it looks like
Data search in WISDOM
Data search and Metadata
Outlook
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WISDOM System
Slide 3http://wisdom.eoc.dlr.de/Elvis
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WISDOM System: Content in terms of topics
Climate Change andVulnerability Analyses
Analyses of Legal System
Training, CB
InstitutionalMapping
Landuse ChangeSlide 4
Water quantity,demand, reliability
Socio Economic Changes
Basin characteristicsEO based Monitoring
Water Quality, Pollution
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Statisticaldata
PDF documentsin-situ sensorobservations
Raster data
Vector data
WISDOM System: Content in terms of data types
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WISDOM System: Wrap up
Vast amount of data
Different data types in one system
Different semantics of data
How to find appropriate data within the information system?
We use OGC compliant metadata to describe every dataset, be it geographic or not!
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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
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Need for Metadata: what is the content of metadata?
Which Which region region does it cover?does it cover?
Which Which projection?projection?
Who is the point Who is the point of contact?of contact?
Which Which timetime does does it cover?it cover?Who provided Who provided
the metadata?the metadata?
How was it How was it produced?produced?
What about quality?What about quality?
Which Which topictopic??
?
Metadata provide answers to these questions!Metadata provide answers to these questions!
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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
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Need for Metadata: WISDOM Profile
Discussion in project, what information is needed as Metadata
Definition of thesaurus to categorize data, such as Infrastructure, Hydrology
Lengthy process to agree upon shared vocabulary! We all needed to speak the same language
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data
Need for Metadata: Search in WISDOM
CSW WMS
Meta-dataMeta-
dataMeta-data
describe
Search for Data
XML
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Data search in WISDOM: how does it look like?
No freetext search to avoid frustration: homonyms, synonyms etc
Search data by applying filter Time Topic Region Datatype
Search data by applying filter
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Data search in WISDOM: Example
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Data search in WISDOM: Example (ctd)
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Data search in WISDOM: Example (ctd)
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Data search in WISDOM: Example (ctd)
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Request: Intersection of bounding box information <ogc:Intersects>
Metadata
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Data Search and Metadata: Keywords in Metadata
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English and Vietnamese
Keyword „Infrastructure“ written to Metadata
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Data Search and Metadata: Search results
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Vector Data Statistics Document
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Tools that support the generation of metadata for users
Altova Formular Tool
Online Metadata Tool (Data Entry Protal)
These ensure that metadata fit to search and search fits to metadata.
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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
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