Solving the Privacy Problem
This method produces remarkably detailed data on human movements without compromising human privacy by:

1) keeping the precise, valuable, data on movements in public places -- where a precise record of the movements does not make it possible to identify the person; and,

2) blurring the data on movements in areas that are not public.

Detailed maps (like those built into portable GPS navigation units) make it possible to identify public areas.

In effect, the method is a filter -- keeping the useful data on public movements, and blurring the toxic data on movements in private places.

The net result is that it is impossible to know from whom a given track is drawn. The location data is anonymized, and privacy is protected.