Flagging locations not on settlements

[maning]

Using FB's settlement data, I did a quick raster on point sampling of the data here. The goal of this quick viz is to identify (and later, filter out) what is potentially wrong school location. The premise here is that a school that is not within a settlement area should be wrong.

Green is on settlement, Magenta not on settlement

~58% is not contained within settlement.

I did a quick check and I confirm a lot of them are indeed wrong location. Meaning no structure exist in satellite imagery.

We can definitely improve it because the settlement raster in some cases do not include the whole settlement areas thereby missing some valid school locations particularly when the point was on the school grounds where no building exist.

cc @govvin