Changes

We don't need to discard outliers, per se, just find a layer where outliers are singletons. One way to do this is to take the highest layer with a single hull (or two hulls or three hulls, etc.) If a layer never has a hull, then presumably it only has a single location or a line of locations (note that it is possible for a line to have more than 2 locations both because of multitons and because of perfect alignment, given our Google Maps accuracy), so we can discard it. The base table for this approach is '''hcllayer'''. The variables are '''highest1hulllayer''', highesttwohulllayer, and highestthreehulllayer in the '''highesthulllayer''' table.