>Because they say they have 68 billion observations, certainly combining each to each 4 times is not possible. There must be some heuristic and/or trick to it.

>Because they say they have 68 billion observations, certainly combining each to each 4 times is not possible. There must be some heuristic and/or trick to it. Maybe define heuristics for what ISN'T useful first to pare down the data set (looking for negatives), then focus on the sort where you're actually looking for positives? When I'm sorting photos for art purposes, I shoot a lot, years at a time, then spend a month or two sorting into albums, I actualy lost hours of work because I had to restore my phone from a backup recently. But the general idea, when doing a completely manual process, is you grab say, 1kish of 20k images, then from there further split them into 3-4 albums. Now if they were astronomy photos then you could go into that set of about 500 and manually look, think what's a heuristic to get me from where I started to here more quickly. (Sorry if articulating myself poorly, this site spikes my anxiety -- if I give useful information people just siphon it up, but if you give an opinion they don't like, folks get real ornery.)