RGeo snippets
RGeo is a wonderfully efficient and complex Ruby library to help you talk to PostGIS and take advantage of it.
Here's a snippet I made (simple question) to find pois close to a location:
def self.closest(lon, lat, radius)
point = GEOFACTORY.point(lon, lat).projection
where{st_distance(coords, point)<radius}
end
It's using squeel to make the sql generation much easier (hope Sqeel makes it into rails4). 2.5ms on my slow MBA, not calculating haversine distances, optimized with an index. What else could you hope for? Butter?