This is the type of approach to the problem that is made from international organizations, it seeks an objective method of measuring the city based on satellite observation, do not require the collaboration of anyone, only have a satellite. It reminds me of when the English made cardboard tanks to deceive the German photo-interpreters by simulating huge military bases. Well, our point of view is that the systematization of the transformation processes of the city must be the source of data, it is as if the Germans could have put an accountant at the exit door of the factories of tanks of England and count well Those who destroy, would surely have more truthful information than looking at the stains of an aerial photograph.
Can we intervene in the processes of urban change to count? Count people, houses, parks, endowments, infrastructures ... If we can not, then we will have to opt for the satellite or ... the drones. But it is as if a bank inventoriease from time to time its balance thanks to that its employees measure with a meter the volume of tickets that are in the safe, instead of having a computer system that updates to the second its balance because all the transactions Are automated.
Our purpose is to provide cities with tools to control their processes of change and build certain and complete inventories of their content. Very low cost cloud tools ($ 100 / month approx) using collaborative methods (OSM has set the tone and demonstrated success). Although the truth is that each city addresses the problem differently, there is no political will to share the data, nor is there a national authority, much less a global one that requires it. Therefore it will be necessary to continue measuring with the satellite.
(Translated from Spanish by google)