Handle some GeoNetwork specific coding (e.g. OGC:WMS* protocol in
onlineResource maps to the specific wms format in CKAN)
Provide mapping from GeoNetwork categories into CKAN groups
Some schemas provide GML elements with the old namespace URI
http://www.opengis.net/gml while the standard CKAN CSW harvester
parses elements with the http://www.opengis.net/gml/3.2 namespace.
This harvester enables both URIs.
Since GeoNetwork provides also front-end services, the harvester may
build some extras fields containing URL pointing to well-known
services (e.g. the extra value gn_view_metadata_url will
automatically be created with a value of the related entry in
geonetwork:
http://yourgnportal/geonetwork/srv/it/metadata.show?uuid=arw_3km_High_cloud_cover_HCY_20150323T000000000Z).