This isn't anything most people would care about, but I do some GIS work and if you enjoy the process of taking the Very Obvious To a Human and explaining how t

This isn't anything most people would care about, but I do some GIS work and if you enjoy the process of taking the Very Obvious To a Human and explaining how to do ... whatever ... to a handful of sand and tamed lightning, well, there's just so many problems to solve. Just as an example, when you look at land parcels, you often get these irritating slivers (or splinters, even more apt because they are a pain and you have to dig them out) of land. You and I can look at a plot and point one out, but to a computer ... Well, one of the hallmarks of a splinter is that there's an awful lot of fencing but very little land. Or put another way, a lot of perimeter to area enclosed. Simple division doesn't suffice here, because the end result ought to be a dimensionless number so that scale doesn't interfere. Alright, perimeter squared divided by area. The lowest you can get is a little over twelve, for a circle. A square gets you sixteen. But a splinter might give you a value well over a hundred. Now, this sounds nice. You've got some values that are no gos (anything under twelve indicates an error), a reasonable bottom limit, a range where a human ought to take a look at it, and then a third range where you just say, "Yeah, that's a splinter alright, no need to bother a human." Sounds good. But then ... Wyoming. Scale does end up mattering. A parcel that was two feet across and a hundred long has the same "sliver value" as one that is two hundred feet across and ten thousand feet long. Yet the latter is still quite useful. You can run a road through it and tack on some strip malls. So it isn't useless. Okay, so you say "that's great, we'll just set a lower bound on the shortest side, anything bigger than that and you'll have to reconsider." ... but we've assumed that we have handy little rectangles and that we know what the sides are. It's GIS. We have a bag of points tracing the outline of a polygon. It isn't necessarily just four points. Each side might have a bunch of points that are roughly co-linear. You and I can look at it and say "Yeah, that's a rectangle alright," but the computer cannot. And so here I am trying to develop an algorithm to determine how many sides a human would see versus just this list of points. All so I can better define my splinters. Problems like this abound and they're quite interesting to think about. It's one of my favorite parts of programming and it requires some deep introspection, some meta-cognition: how do I recognize this, anyway? What is going on in my mind that I can do this?