allow "docid override" queries to include the results of a "normal" query - if the operator is left null, it acts as the usual override, otherwise UNION and INTERSECT modes can be used to either augment or refine the results. this is for incorporating semantic+spatial+keyword queries into one query operation/result
allow "docid override" queries to include the results of a "normal" query - if the operator is left null, it acts as the usual override, otherwise UNION and INTERSECT modes can be used to either augment or refine the results.
this is for incorporating semantic+spatial+keyword queries into one query operation/result