Human population within a distance, from any point in the world.
Select a radius and click on the map.
Estimated population within circle in 2015:
(Calculations will take up to a minute at busy times and for larger radiuses.)
The data is the Global Human Settlement Layer population grid for 2015. It is known to be less accurate for small areas, especially where there has been rapid change in population.
I convert the GeoTIFF files from the GHSL into populations at points and then store this in an SQLite database. An API in C# ASP.NET running on an Azure Web App then serves that with some geographical processing included.
The maximum radius is set to 50km, it would get slow above that. I set the minimum radius to 3km because otherwise some city-centre populations are likely to be very wrong and I can't be bothered fielding all the "your amateurish tool gives completely spurious information and you should be ashamed of yourself, you disgrace" type comments that would generate.
I'll probably release the source code of the data preparation steps if I get time.
I probably won't add any features.