Add additional fields to core Dataset

[JJediny]

Test on https://demo.jkan.io/data.json

Using https://labs.data.gov/dashboard/validate data.json v1.1

[JJediny]

RDF DCAT to CKAN dataset mapping

The following table provides a generic mapping between the fields of the dcat:Dataset and dcat:Distribution classes and
their equivalents on the CKAN model. In most cases this mapping is deliberately a loose one. For instance, it does not try to link
the DCAT publisher property with a CKAN dataset author, maintainer or organization, as the link between them is not straight-forward
and may depend on a particular instance needs. When mapping from CKAN metadata to DCAT though, there are in some cases fallback fields
that are used if the default field is not present (see RDF Serializer for more details on this.

This mapping is compatible with the DCAT-AP v1.1.

DCAT class	DCAT property	CKAN dataset field	CKAN fallback fields	Stored as
dcat:Dataset	-	extra:uri		text	See note about URIs
dcat:Dataset	dct:title	title		text
dcat:Dataset	dct:description	notes		text
dcat:Dataset	dcat:keyword	tags		text
dcat:Dataset	dcat:theme	extra:theme		list	See note about lists
dcat:Dataset	dct:identifier	extra:identifier	extra:guid, id	text
dcat:Dataset	adms:identifier	extra:alternate_identifier		text
dcat:Dataset	dct:issued	extra:issued	metadata_created	text
dcat:Dataset	dct:modified	extra:modified	metadata_modified	text
dcat:Dataset	owl:versionInfo	version	extra:dcat_version	text
dcat:Dataset	adms:versionNotes	extra:version_notes		text
dcat:Dataset	dct:language	extra:language		list	See note about lists
dcat:Dataset	dcat:landingPage	url		text
dcat:Dataset	dct:accrualPeriodicity	extra:frequency		text
dcat:Dataset	dct:conformsTo	extra:conforms_to		list	See note about lists
dcat:Dataset	dct:accessRights	extra:access_rights		text
dcat:Dataset	foaf:page	extra:documentation		list	See note about lists
dcat:Dataset	dct:provenance	extra:provenance		text
dcat:Dataset	dct:type	extra:dcat_type		text	As of DCAT-AP v1.1 there's no controlled vocabulary for this field
dcat:Dataset	dct:hasVersion	extra:has_version		list	See note about lists. It is assumed that these are one or more URIs referring to another dcat:Dataset
dcat:Dataset	dct:isVersionOf	extra:is_version_of		list	See note about lists. It is assumed that these are one or more URIs referring to another dcat:Dataset
dcat:Dataset	dct:source	extra:source		list	See note about lists. It is assumed that these are one or more URIs referring to another dcat:Dataset
dcat:Dataset	adms:sample	extra:sample		list	See note about lists. It is assumed that these are one or more URIs referring to dcat:Distribution instances
dcat:Dataset	dct:spatial	extra:spatial_uri		text	If the RDF provides them, profiles should store the textual and geometric representation of the location in extra:spatial_text and extra:spatial respectively
dcat:Dataset	dct:temporal	extra:temporal_start + extra:temporal_end		text	None, one or both extras can be present
dcat:Dataset	dct:publisher	extra:publisher_uri		text	See note about URIs
foaf:Agent	foaf:name	extra:publisher_name		text
foaf:Agent	foaf:mbox	extra:publisher_email	organization:title	text
foaf:Agent	foaf:homepage	extra:publisher_url		text
foaf:Agent	dct:type	extra:publisher_type		text
dcat:Dataset	dcat:contactPoint	extra:contact_uri		text	See note about URIs
vcard:Kind	vcard:fn	extra:contact_name	maintainer, author	text
vcard:Kind	vcard:hasEmail	extra:contact_email	maintainer_email, author_email	text
dcat:Dataset	dcat:distribution	resources		text
dcat:Distribution	-	resource:uri		text	See note about URIs
dcat:Distribution	dct:title	resource:name		text
dcat:Distribution	dcat:accessURL	resource:url		text	If accessURL is not present, downloadURL will be used as resource url
dcat:Distribution	dcat:downloadURL	resource:download_url		text
dcat:Distribution	dct:description	resource:description		text
dcat:Distribution	dcat:mediaType	resource:mimetype		text
dcat:Distribution	dct:format	resource:format		text	This is likely to require extra logic to accommodate how CKAN deals with formats (eg ckan/ckanext-dcat#18)
dcat:Distribution	dct:license	resource:license		text	Note that on the CKAN model, license is at the dataset level
dcat:Distribution	adms:status	resource:status		text
dcat:Distribution	dcat:byteSize	resource:size		number
dcat:Distribution	dct:issued	resource:issued		text
dcat:Distribution	dct:modified	resource:modified		text
dcat:Distribution	dct:rights	resource:rights		text
dcat:Distribution	foaf:page	resource:documentation		list	See note about lists
dcat:Distribution	dct:language	resource:language		list	See note about lists
dcat:Distribution	dct:conformsTo	resource:conforms_to		list	See note about lists
spdx:Checksum	spdx:checksumValue	resource:hash		text
spdx:Checksum	spdx:algorithm	resource:hash_algorithm		text