Wider Than It Looks

To find charging stations within 5 km of a point at latitude 60 degrees north, an engineer builds a bounding box by adding and subtracting the same delta, about 0.045 degrees, to both latitude and longitude. Results near the east and west edges are missing. What went wrong?

Bounding boxes are only valid at the equator, so any radius search away from it has to fall back to scanning the full table

A degree of longitude shrinks with the cosine of latitude, so at 60 degrees the longitude delta must be about twice the latitude delta

A degree of longitude grows with the cosine of latitude, so the longitude delta should be about half the latitude delta at that point

The bounding box must be computed in radians before being applied to a decimal degree column, which is why the east west span is short