older ISO 19115 to DCAT mappings (UK, W3C, EC)

[PeterParslow]

Listed in "GEMINI" (the UK Metadata profile) GitHub issue: agiorguk/gemini#41

• the issue itself contains a mapping (endorsed by UK government's Geospatial Commission) from GEMINI (subset of ISO 19115:2003/19139 to DCAT v2) - update to DCAT v3 in progress
• The W3C mapping, on which that is largely based, is at https://www.w3.org/2015/spatial/wiki/ISO_19115_-_DCAT_-_Schema.org_mapping
• Andrea Perego’s (European Commission) ISO 19139 - DCAT mapping provides more detail e.g. the range of each element, and also maps somethings outside the DCAT namespace(s). https://github.com/GeoCat/iso-19139-to-dcat-ap/blob/master/documentation/Mappings.md

@rob-metalinkage