[godelski]

I'm curious how exact you would need. Like within 90%? 80%? 50%?

For those that want to follow up on this, you could use current satellite imagery to make population estimates, but it wouldn't be really accurate. You could wait for companies like Planet Labs[1] to get daily photos of the Earth (IIRC 4m resolution), and increase accuracy. You could also hire pilots to strap a camera and survey the interested areas. There are also, IMO, unethical spins (especially in oppressive regimes) that you could do with that data (ie: civilian surveillance). Or even cheaper, use drones (because you don't need daily or real time surveillance). That could also have other spinoffs. Or you could literally just send people to go count. Don't know which would be the cheapest.

[1] https://www.planet.com

[sdiq]

I am not exactly an expert on matters demography but I think 50% would be low. At the moment, we have a study that was done by one of the UN agencies and the figures they came up with seem very disputed. They used 1975 census as the base for their extrapolations. Quite a lot happened since and their figures are not really believable.