EPOS

I suggest that we add "none" to the Collar Headwork Type vocab. The
alternative is to leave it empty for all boreholes that do not have a
Collar Headwork. But in the latter case, it is not possible to make a
distinction between boreholes with no collar headwork and boreholes with
no information. Examples: ocean drilling (hole left open with out
completion), many of the geotechnical drillings in the geosurvey
databases, ...

<skos:Concept
rdf:about="https://data.geoscience.earth/ncl/CollarHeadworkType/none">
<skos:inScheme rdf:resource="https://data.geoscience.earth/ncl/CollarHeadworkType"/>
<skos:prefLabel xml:lang="en">none</skos:prefLabel>
<skos:topConceptOf rdf:resource="https://data.geoscience.earth/ncl/CollarHeadworkType"/>
<skos:definition xml:lang="en">Collar headwork is not present.</skos:definition>
</skos:Concept>