I ran into the Catalog Services for the Web (CSW) when I wanted to see which public geographical data was available for the Netherlands: the Nationaal GeoRegister (NGR) makes use of it. Apart from showing available datasets, the page also gives information about the underlying technology: CSW.
On the Catalogue Service page of the Open Geospatial Consortium (OGC) Standards page the full Specification for the latest version (2.0.2) can be found. See the References section for more links.
The Catalogue Service page describes:
Catalogue services support the ability to publish and search collections of descriptive information (metadata) for data, services, and related information objects. Metadata in catalogues represent resource characteristics that can be queried and presented for evaluation and further processing by both humans and software. Catalogue services are required to support the discovery and binding to registered information resources within an information community.
One of the ways to get information about and from a CSW catalog is the GET method of the HTTP protocol. By specifying a properly formed URL in a internet browser the requested information is shown in the browser window.
The CSW R package provides functions that use the same GET method to place the result in an R object as a data.frame, xml_document or integer variable. Operations are recognized by the CSW interface in the URL by the phrase request=. The package has functions for the read-only Operations. Also included are some utility functions.
This package is until now only tested on the
Nationaal GeoRegister(NGR)
catalog with CSW 2.0.2. By using the CSW_set_url and CSW_set_version functions these values will be replaced by the ones provided by the user.
Let me know if you encounter problems with other catalogs: maybe these can be solved.
devtools::install_github("HanOostdijk/CSW",build_vignettes = T)
The folder manual_pdf contains the package manual and vignette in PDF format.
- Nationaal GeoRegister (NGR) : hub for location spatial information for the Netherlands (in Dutch)
http://nationaalgeoregister.nl/geonetwork/srv/dut/search - Publieke Dienstverlening op de Kaart (PDOK) : platform for open spatial data (in Dutch)
https://www.pdok.nl/ - Description APIs (including CSW) for PDOK environment (in Dutch)
https://pdok-ngr.readthedocs.io/. - Description of GeoServer services (including CSW)
https://docs.geoserver.org/latest/en/user/services/index.html - Catalogue Service page of the Open Geospatial Consortium (OGC)
http://www.opengeospatial.org/standards/cat - Specification of Catalog Services for the Web (CSW) version 2.0.2
http://portal.opengeospatial.org/files/?artifact_id=20555 - GeoServer Tutorial section about queries
https://docs.geoserver.org/stable/en/user/tutorials/cql/cql_tutorial.html - GeoServer reference for ECQL queries
https://docs.geoserver.org/stable/en/user/filter/ecql_reference.html#filter-ecql-reference - Examples for DescribeRecords by FrieseWoudloper
https://gist.github.com/FrieseWoudloper/b7cad022cb75ba531ebbececf5fc85db
To my knowledge no other R packages concerning CSW exist.