One PostgreSQL feature I recently revisited is earthdistance, a nice reminder that not every problem involving latitude and longitude requires a full GIS stack. The earthdistance extension provides a straightforward way to calculate great-circle distances between locations on Earth. Combined with PostgreSQL’s cube extension, ll_to_earth() converts latitude and longitude into a representation that earth_distance() can use to calculate distance in meters. It also provides earth_box(), which is useful for nearby-location searches. An indexed bounding-box search can quickly narrow the candidates, followed by earth_distance() to determine which points actually fall within the desired radius. There’s also a simpler approach using PostgreSQL’s built-in point type and the <@> operator, which returns distances in statute miles. There are limitations: earthdistance models Earth as a sphere, and it isn’t a replacement for PostGIS when you need complex geometries, coordinate systems, spatial relationships, or serious GIS analysis. But that’s exactly why I like it. If your application just needs to answer something like “Which locations are within 10 miles of this point?”, PostgreSQL may already have all the geospatial functionality you need.