I am slightly confused as to what is meant by "urban extent" and "settlement points" - please could you send me a definition? Also, I have found the global map which shows "urban extent" - which I guess is the areas of the Earth's surface which are covered by urban areas. I am wondering if you, or anyone else you know of, has a time-series of such maps, showing how urban coverage has changed over time?
The main difference between the settlement points and the urban extent mask is that the extents indicate the spatial area of the settlement. The points are simply a lat-lon coordinates with name and population size. The mask gives area of each urban place for large places it includes many settlements as well as the population (from the GRUMP surface). Unfortunately, there is no time-series available, not one that indicates change in land area that is urban.