/// <summary>User drills down on the specified range.</summary>
public TopDocs DrillDown(DoubleRange range)
{
// Passing no baseQuery means we drill down on all
// documents ("browse only"):
DrillDownQuery q = new DrillDownQuery(null);
ValueSource vs = GetDistanceValueSource();
q.Add("field", range.GetFilter(GetBoundingBoxFilter(ORIGIN_LATITUDE, ORIGIN_LONGITUDE, range.Max), vs));
DrillSideways ds = new SearchDrillSideways(searcher, config, vs);
return(ds.Search(q, 10).Hits);
}