Catalog Service for the Web

Catalog Service for the Web (CSW), sometimes seen as Catalog Service - Web, is a standard for exposing a catalogue of geospatial records in XML on the Internet (over HTTP). The catalogue is made up of records that describe geospatial data (e.g. KML), geospatial services (e.g. WMS), and related resources.

CSW is one part (or "profile") of the OGC Catalog Service, which defines common interfaces to discover, browse, and query metadata about data, services, and other potential resources. Version 2.0 of the specification was released in May 2004. The most recent release is 2.0.2, which was published in 2007.[1]

The records are in XML according to the standard. Typically the records include Dublin Core, ISO 19139 or FGDC metadata, encoded in UTF-8 characters. Each record must contain certain core fields including: Title, Format, Type (e.g. Dataset, DatasetCollection or Service), BoundingBox (a rectangle of interest, expressed in latitude and longitude), Coordinate Reference System, and Association (a link to another metadata record).

Operations defined by the CSW standard include:[1][2]

Requests can encode the parameters in three different ways:

Responses are in XML.

Sample interaction

GeoServer implements many OGC standards, including CSW. An example of the DescribeRecord operation is as follows:[3]

http://localhost:8080/geoserver/csw?service=CSW&version=2.0.2&request=DescribeRecord&typeName=gmd:MD_Metadata

A (truncated) response:

<?xml version="1.0" encoding="UTF-8"?>
<csw:DescribeRecordResponse xmlns:csw="http://www.opengis.net/cat/csw/2.0.2" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/cat/csw/2.0.2 http://localhost:8080/geoserver/schemas/csw/2.0.2CSW-discovery.xsd">
<csw:SchemaComponent targetNamespace="http://www.opengis.net/cat/csw/2.0.2" schemaLanguage="http://www.w3.org/XML/Schema">
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:gco="http://www.isotc211.org/2005/gco" xmlns:gmd="http://www.isotc211.org/2005/gmd" targetNamespace="http://www.isotc211.org/2005/gmd" elementFormDefault="qualified" version="2012-07-13">
<!-- ================================= Annotation ================================ -->
 <xs:annotation>
 <xs:documentation>Geographic MetaData (GMD) extensible markup language is a component of the XML Schema Implementation of Geographic Information Metadata documented in ISO/TS 19139:2007. GMD includes all the definitions of http://www.isotc211.org/2005/gmd namespace. The root document of this namespace is the file gmd.xsd. This identification.xsd schema implements the UML conceptual schema defined in A.2.2 of ISO 19115:2003. It contains the implementation of the following classes: MD_Identification, MD_BrowseGraphic, MD_DataIdentification, MD_ServiceIdentification, MD_RepresentativeFraction, MD_Usage, MD_Keywords, DS_Association, MD_AggregateInformation, MD_CharacterSetCode, MD_SpatialRepresentationTypeCode, MD_TopicCategoryCode, MD_ProgressCode, MD_KeywordTypeCode, DS_AssociationTypeCode, DS_InitiativeTypeCode, MD_ResolutionType.</xs:documentation>
</xs:annotation>

Versions

Versions 2.0.0, 2.0.1 and 2.0.2 are subtly different, and different vendors implement them with variations.[4] Typically a CSW server will accept requests in one CSW version only, and it is up to the client to be flexible. e.g. ESRI Geoportal can be configured to harvest documents from CSW servers of a variety of versions and vendor variants [5] such as "GeoNetwork CSW 2.0.2 APISO".

See also

References

  1. 1 2 "OpenGIS Catalogue Service Implementation Specification". Open Geospatial Consortium (OGC). 2007-02-23.
  2. ↑ "GeoServer | Catalog Services for the Web (CSW) features".
  3. ↑ "Catalog Services for the Web (CSW) tutorial". GeoServer 2.8.x User Manual. Retrieved 2015-03-24.
  4. ↑ "GeoNetwork's cross-platform interoperability".
  5. ↑ "ESRI Geoportal".

External links

This article is issued from Wikipedia - version of the 4/8/2015. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.