[_mulder_]

Perhaps the decay times on the trails is too long, but I can't really detect any patterns here, other than that people seem to walk, run, cycle and drive down roads. After a few mins, all this seems to do is highlight the road structure of a city. A shorter trail decay would highlight the people commuting and show activity for transport type by time of day.

Another interesting metric would be to adjust brightness based on length of journey.

[pveugen]

Good point. I played around with different decay times a lot, but it was very hard to settle on a decay time and opacity settings that worked for most cities, since the data set from city to city was varying in size. If I would re-render the movies, I'd definitely do try renders with lower decay times, especially for cities like NY, LA, etc.

[saraid216]

It might be interesting to see whether or not an ideal decay time correlates with anything.

[mahesh_rm]

Using a wavelet time frequency analysis is what they generally do to highlight these kinds of patterns when dealing with brain activations of neural populations. It gives you an idea of power of a specific frequency over time [e.g., http://www.lauriefrick.com/wp-content/uploads/2011/07/wavlet...]. And apparently it's already been used for analogous purposes: [ http://www.paramics-online.com/downloads/technicaldocs/wavel...] :-)