CSW: Unterschied zwischen den Versionen

Version vom 4. Oktober 2007, 02:34 Uhr

'Catalog Services for the Web' from OGC.

See also OAI-PMH and especially HowTo OAI-PMH for harvesting geo-metadata.

Specifications and software:

• OGC-CSW 2.0.1, OGC Catalogue Services Specification, version 2.0.1 OGC 04-021r3.
• GeoNetwork opensource v2.1 (GN) the Reference Implementation of CSW.

The following OGC specifications are also relevant for CSW (!):

• OpenGIS Web Services Common Specification, version 1.0.0 OGC 05-008c1
• Filter Encoding Implementation Specification, version 1.1.0 OGC 04-095
• Geographic information -- Geography Markup Language OGC 03-105r1

Remarks

CSW is not the only catalog specification from OGC. There is a competing specification called 'ebRIM Profile' (!!!) :-O.

Harvesting is not yet implemented in GeoNetwork (GN) - the reference implementation (!!!). Question from the GeoNetwork-devel mailing list: "Why the CSW harvesting compliant with the OGC spec. is not implemented in GN 2.1". Answer (26.09.2007 14:07): " The CSW harvesting operation has a not well defined sematics and is not flexible enough to allow a good harvesting. The specs are continually changing making its usage useless. I'm finishing to implement the OAI-PMH harvesting protocol and, IMHO, it outperforms CSW harvesting on all aspects.".

Core catalogue schema

The following is an example of a (‘qualified’ core metadata set of the Dublin Core Metadata Initiative (Source: OGC 04-021r3):

 <?xml version="1.0" encoding="UTF-8"?>
 <cat:Record
   xmlns:cat="http://www.opengis.net/cat"
   xmlns:dc="http://purl.org/dc/elements/1.1/"
   xmlns:dct="http://purl.org/dc/terms/"
   xmlns:csw="http://www.opengis.net/cat/csw"
   xmlns:iso19115TopicCategory="http://www.isotc211.org/"
   xmlns:dcmiBox="http://dublincore.org/documents/2000/07/11/dcmi-box/">
   <dc:creator>U.S. Geological Survey</dc:creator>
   <dc:contributor>State of Texas</dc:contributor>
   <dc:publisher>U.S. Geological Survey</dc:publisher>
   <dc:subject>Elevation, Hypsography, and Contours</dc:subject>
   <iso19115TopicCategory>Elevation</iso19115TopicCategory>
   <dct:abstract>Elevation data collected for the National Elevation
     Dataset (NED) based on 30m horizontal and 15m vertical accuracy.
   </dct:abstract>
   <dc:identifier>f264-77d2-09ce-aa39-f0f0</dc:identifier>
   <dc:relation>g</dc:relation>
   <dc:source>h</dc:source>
   <dc:rights>i</dc:rights>
   <dc:format>j</dc:format>
   <dc:type>Service</dc:type>
   <dc:title>National Elevation Mapping Service for Texas</dc:title>
   <dct:modified>2004-03-01</dct:modified>
   <dct:spatial>
     <Box projection="EPSG:4326" name="Geographic">
       <northlimit>34.353</northlimit>
       <eastlimit>-96.223</eastlimit>
       <southlimit>28.229</southlimit>
       <westlimit>-108.44</westlimit>
     </Box>
   </dct:spatial>
   <dc:language>en</dc:language>
 </cat:Record>