Geographic Subject headings are field 651 and Subfield 2 tells us the source for the heading (on what authority do we use this term to refer to the topic?). Links to what are the authorities.
The authority code used in our field is "gtt", we find here is GOO-trefwoorden thesaurus (Den Haag: Koninklijke Bibliotheek), about which we find "Nederlandse Basisclassificatie is a numeric root-classification...".
Long way of saying I did the research and it is legitimate data, which we might as well not bother to purge because we will end up reimporting it back from WorldCat in the future, for these records or elsewhere. It can continue to live in the Folio "instance" bib records.
A proprietary coding scheme, as used in this particular authoritative subject heading thesaurus, is not a useful link to display in the facets. No one knows these codes for geographic regions, and in every case there will be a normal text heading that really gets the data they want.
We could exclude 651#7 fields from Folio import but there are absurd amounts of these subject thesauri, and a lot of the data in there is usable terms.
But the data exists to exclude these alternate thesauri from VuFind display (saying nothing about how that gets done, but...)
if VuFind can
examine the subject fields and
exclude 6xx fields with:
2nd indicator 7 and
subfield 2 containing "gtt"; this condition is probably sufficient do do the job without checking 2nd indicator value
then that would get this particular thesaurus off screen.
Giving this issue a general title in case we find more of these, but "gtt" is the only one seen yet.
It all starts with, Why do I see a numeric code in the Geographic Subject facet?
At least it's in the old catalog too. MilCat
Geographic Subject headings are field 651 and Subfield 2 tells us the source for the heading (on what authority do we use this term to refer to the topic?). Links to what are the authorities. The authority code used in our field is "gtt", we find here is GOO-trefwoorden thesaurus (Den Haag: Koninklijke Bibliotheek), about which we find "Nederlandse Basisclassificatie is a numeric root-classification...".
Long way of saying I did the research and it is legitimate data, which we might as well not bother to purge because we will end up reimporting it back from WorldCat in the future, for these records or elsewhere. It can continue to live in the Folio "instance" bib records.
A proprietary coding scheme, as used in this particular authoritative subject heading thesaurus, is not a useful link to display in the facets. No one knows these codes for geographic regions, and in every case there will be a normal text heading that really gets the data they want.
We could exclude 651#7 fields from Folio import but there are absurd amounts of these subject thesauri, and a lot of the data in there is usable terms.
But the data exists to exclude these alternate thesauri from VuFind display (saying nothing about how that gets done, but...) if VuFind can
then that would get this particular thesaurus off screen.
Giving this issue a general title in case we find more of these, but "gtt" is the only one seen yet.