Taxon search: stratigraphy filter field

[Erikdzo]

What field is used for stratigraphy filtering in Solr taxon endpoint? Currently stratigraphy_hierarchy is used in the front-end but it does not exist in Solr, leading to errors.

[ollehints]

We cannot use stratigraphy_hierarchi as the age range is provided by two stratigraphic units - where it appears (FAD), and disappears (LAD). Added couple of index fields, easiest is to use numeric fields fad_age_base and lad_age_top.
Stratigraphic search should take the age range from a chronostratigraphic units that a user is interested in and then check for overlap with the age range of the taxon.
For instance, a user wants to find all taxa that occur in the Ordovician. He then selects Ordovician from autocomplete, frontend gets also base and top numeric ages (https://api.geoloogia.info/solr/stratigraphy?q=*&fq=stratigraphy_en:Ordovician&fl=stratigraphy_en,stratigraphy,age_base,age_top): 485.4 and 443.8
Then the stratigraphic filter would be:
https://api.geoloogia.info/solr/taxon?q=*&fq=fad_age_base:[443.8%20TO%20*]&fq=lad_age_top:[*%20TO%20485.4]