The common item that lets you find a photo’s location in a GPS track is the time it was taken. In database terminology, time is the join column.
Since I’m starting with photos that are already timestamped, I want to be able to look up their timestamps in some sort of GPS database to see whether there’s a recorded time/location event near that time. Unfortunately, my initial perusal of a couple of geo-extensions to well known databases (SpatialLIte, PostGIS), show a generous helping of geometry-oriented query capabilities but no obvious time-query capabilities.
It could be that time-indexing is so simple compared with spatial indexing that what I’m looking for is just swamped in the documentation, or it could be that I’ll have to dig some more.