Deutscher Wetterdienst Markus Heene, DWD [email protected] DAR Metadata.
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Transcript of Deutscher Wetterdienst Markus Heene, DWD [email protected] DAR Metadata.
DAR Metadata Catalog 24.09.2010 Page: 2
Agenda Welcome
Notes
Metadata record types & associated datasets
DAR Metadata Identifiers
Introduction to DWD DAR metadata approach for GISC – conformance part
Requirements for DWD DAR metadata generator
DWD DAR Metadata generator – architecture
XML template for DAR metadata
Usage and some facts
Points for discussion
DAR Metadata Catalog 24.09.2010 Page: 3
Notes I’m not member of IPED-MDI
This presentation is an introduction to DAR Metadata
For this presentation– DAR Metadata are XML files
– Are well-formed XML documents
– Validate against a schema (ISO 19139)
– ISO 19139 defines an XML representation for ISO 19115 metadata
This presentation shows DWDs approach to produce DAR Metadata
DAR Metadata Catalog 24.09.2010 Page: 4
DAR Metadata Catalog 24.09.2010 Page: 5
Metadata record types & associated datasets Metadata Record A describes a dataset of bulletins which are stored in the 24-hour cache of
the GISC.
The metadata record A is equivalent (although more informative) to a record in WMO vol C1 & describes the normal contents of this type of bulletin; for example SYNOPS from several observation stations; including MLO (Mauna Loa, Hawaii).
Metadata record B describes a long-term climate record from station MLO which is comprised of a collection of SYNOPTIC observations from, say, 1954.
DAR Metadata Catalog 24.09.2010 Page: 6
Metadata record types & associated datasets Whilst both datasets are continually changing, both metadata records are ‘quasi-static’; only
needing to be changed when the observation regime changes (i.e. a new instrument is deployed or the exact observation location changes) The critical differences between records A & B in this example are:
– Temporal extent: A has a relative temporal extent in any 24-hour period, whilst B has a temporal extent from 1954 to (almost) present day;
– Citation authority: authority for A is int.wmo.wis, whilst B is gov.noaa
– Quality control: the dataset described by B may have undergone additional quality control to validate the observation record for inclusion in a long-term archive
Whilst the meeting noted that there may be significant overlap between A and B, one cannot assume that overlap exists. The meeting concluded that metadata records A and B describe entirely different products!
DAR Metadata Catalog 24.09.2010 Page: 7
DAR Metadata Identifiers urn:x-wmo:md:
– int.wmo.wis
– de.dwd
Separator is “:”
Examples– urn:x-wmo:md:int.wmo.wis::SMAA01EDZW
– urn:x-wmo:md:int.wmo.wis::FCUK31EGRR
– urn:x-wmo:md:cn.gov.cma::NMC.NWP.HCXA05BABJ
Case insensitive check for duplication
Check uniqueness of a DAR Metadata Record– gmd:MD_Metadata/gmd:fileIdentifier
– gmd:MD_Metadata/gmd:dateStamp
DAR Metadata Catalog 24.09.2010 Page: 8
Live Demo
DAR Metadata Catalog 24.09.2010 Page: 9
Introduction to DWD DAR metadata approach for GISC – conformance part
ISO 19139 conformance
WMO conformance
INSPIRE conformance – European Commission Directive (http://inspire.jrc.ec.europa.eu)
– More demanding than ISO
– Implementing guidelines (paper with 74 pages) (http://inspire.jrc.ec.europa.eu/reports/ImplementingRules/metadata/MD_IR_and_ISO_20090218.pdf)
– Increase metadata by ~ 20%
DAR Metadata Catalog 24.09.2010 Page: 10
Requirements for DWD DAR metadata generator Metadata conforms to WMO, ISO 19139 and INSPIRE
Automatic generation of metadata
Basic information is stored in GISC database model
Bulk generation for tests of DAR catalogues
Logging: need to identify easily issues
Extendable and maintainable
Reusable for other components
Easy to distribute
DAR Metadata Catalog 24.09.2010 Page: 11
DWD DAR Metadata generator - architecture
XML template
Database
XSLT templates
read data
DBReader
MetaDataFileGen.
read template
1
2
WorkFacade
3processtemplate
ISO 19139 schema
4 do XSLT
5validate document
6
outputdocument
Metadata
DAR Metadata Catalog 24.09.2010 Page: 12
XML template for DAR metadata
Template is ISO 19139 and INSPIRE conform
Based mainly on examples from Jürgen (DWD) and inspirations from CMA, JMA and Météo France
Nodes you may wonder about:– <gmd:hierarchyLevelName>: map navigation (theme), alternative tag <gmd:MD_TopicCategoryCode> (well-
defined by ISO, only 2 or 3 revelant entries for meteorology in enumeration)
– <gmd:descriptiveKeywords uuidref="GEMET">: we need this for INSPIRE
– <gmd:MD_SecurityConstraints>: based on April 2009 workshop with CMA we use this element for priorities of products
– <gmd:extent uuidref="BBox">: each metadata record should contain one bounding box, in addition this extent contains <gmd:temporalElement> no separate <gmd:extent> for <gmd:temporalElement> (INSPIRE)
– <gmd:dataQualityInfo>: we need this for INSPIRE
DAR Metadata Catalog 24.09.2010 Page: 13
Usage and some facts Usage:
– Whole production is based on ant (all necessary libs, source code for metadata generator are provided)
– Customize build.properties to your needs (check documentation)
– Load basic information for metadata generation into DB
– Type “ant” at CLI that’s it
Facts:– Roughly 1 sec per metadata document on standard PC
– Metadata are reviewed by external company (con terra) received positive feedback, suggestions for improvement are already implemented
– Still prototype software
DAR Metadata Catalog 24.09.2010 Page: 14
DAR Metadata exchange GISC to GISC
– OAI-PMH (Open Archives Initiative Protocol for Metadata Harvesting)
– Example Implementations:
• jOAI http://www.dlese.org/dds/services/joai_software.jsp
• OAICat http://www.oclc.org/research/activities/oaicat/default.htm
NC/DCPCs uploading DAR Metadata to GISC– GTS: file-naming-convention
DAR Metadata Catalog 24.09.2010 Page: 15
Resources and further information IPED-MDI – Final Report
http://www.wmo.int/pages/prog/www/WDM/IPET-MDI-I/report/Report_IPETMDI_I_20100503.doc
INSPIRE Editor - http://www.inspire-geoportal.eu/InspireEditor/
INSPIRE Metadata Implementing Rules - http://inspire.jrc.ec.europa.eu/documents/Metadata/INSPIRE_MD_IR_and_ISO_v1_2_20100616.pdf
DAR Metadata Catalog 24.09.2010 Page: 16
Q&A