Retrieve vector of existing filter valuesSource:
This is a utility function which allows to user to query about the existing possibilities of a given filter name
For a full description of each valid filter_name see
aims_expose_attributes. In the temperature logger dataset,
"subsite" is equivalent to "series"; moreover, note that there is only one
parameter being measured (i.e. water temperature), so the "parameter" filter
contains one single value.
AIMS Datacentre email@example.com