ash_geo and attempting to implement a knn filter, as described here:Unlike a distance search, the “nearest neighbour” search doesn’t include any measurement restricting how far away candidate geometries might be, features of any distance away will be accepted, as long as they are the nearest.
PostgreSQL solves the nearest neighbor problem by introducing an “order by distance” (<->) operator that induces the database to use an index to speed up a sorted return set. With an “order by distance” operator in place, a nearest neighbor query can return the “N nearest features” just by adding an ordering and limiting the result set to N entries.
st_distance function, in both ash_geo and geo_postgis, but don't yet grok how to use it like the <-> operator, to get an unbounded, sorted result set. {long, lat}, and run a knn against that to see the nearest points of interest.nearest function I'm overlooking or some other way to filter and order geometries? Manually run raw SQL?ash_geo tag)