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Alan, thanks for the valuable comments. Yes, GPS seems better option. Cheers. Bin Penn wrote: > Bin, > > As I understand it the real problem is with the spatial resolution and > geography of cell data. The phone company has data on cell handovers, but > they don’t know with any precision (they say) where the cell boundaries are. > Cells overlap and signals bounce off buildings etc. so the geography of > cells is very messy. It also varies depending on demand - a cell that has a > lot of traffic may delay accepting handover from neighbours. Carlo Ratti's > animations of cell occupancy overlaid on maps of Milan shows the extent of > what one can do easily with the data at the moment - ie. generalised contour > maps at an aggregate population level with neither spatial (street) nor > individual person resolution. Gives a nice view of populations ebbing and > flowing over time though. > > GPS data are much nicer... We are working on the Cityware project with > Naranker Dulay, Markus Huebscher and Morris Sloman at Imperial College who > have taken a different approach. They have written an application (a context > logger or "Clogger") for your smartphone which logs your GPS location, IDs > of Bluetooth devices you can see, cell ids, WiFi nodes visible, phone calls, > pictures you have taken, diary appointments, emails and SMS messages etc. > etc. continuously and uploads these to a webpage. It does wonders for your > phone bill and battery life, but also gives beautiful data on what you are > doing with whom, where and when as you move around the city. The problem > (apart from the bill) is that programming phones is tricky and needs to be > redone for different devices. But Clogger is open source so hopefully there > may be people out there who will take on that task... > > Alan Penn > [log in to unmask] > www.vr.ucl.ac.uk > www.spacesyntax.org > > > >> Dear all, >> >> I am very happy to see so many responses on the real time maps (I was >> away for the Chinese new year break). I have a project to track people's >> daily trajectory pattern and then analyze it for city planning. Now the >> most difficult thing is how to get the trajectory datasets. One simple >> way would be to collaborate with cell phone operators, and ask them to >> release all trajectories in one particular geographic area. But it seems >> difficult, simply phone company would not cooperate if there is no >> direct benefit. Another way would be to invite individual people to >> voluntarily participate, and asked them to send an SMS to individual >> respective phone operators to release the trajectory datasets. Anyone >> there had such an experience to share? Would the cell phone operators >> have such duty to do so? Many thanks in advance. >> >> Cheers. >> >> Bin >> >> SteveC wrote: >> >>> Tom Carden wrote: >>> >>> >>>> feeds of live cab locations in San Francisco. I believe Google >>>> offers maps of the same for most US cities, but I don't know how >>>> accessible the data is. >>>> >>> There's a hack for that in google maps hacks from oreilly. >>> >>> have fun, >>> >>> SteveC [log in to unmask] http://www.asklater.com/steve/ >>> >>> >> -- >> -------------------------------------------------------- >> Bin Jiang >> Division of Geomatics >> Dept. of Technology and Built Environment >> University of Gävle, SE-801 76 Gävle, Sweden >> Phone: +46-26-64 8901 Fax: +46-26-64 8828 >> Email: [log in to unmask] Web: http://www.hig.se/~bjg/ >> -------------------------------------------------------- >> >> NordGISci: http://www.hig.se/~bjg/NordGISci/ >> NordGISci2007: http://www.hig.se/~bjg/NordGISci2007/ >> ICA Workshop: http://www.ggy.uga.edu/people/faculty/xyao/Workshop2007/ >> > > -- -------------------------------------------------------- Bin Jiang Division of Geomatics Dept. of Technology and Built Environment University of Gävle, SE-801 76 Gävle, Sweden Phone: +46-26-64 8901 Fax: +46-26-64 8828 Email: [log in to unmask] Web: http://www.hig.se/~bjg/ -------------------------------------------------------- NordGISci: http://www.hig.se/~bjg/NordGISci/ NordGISci2007: http://www.hig.se/~bjg/NordGISci2007/ ICA Workshop: http://www.ggy.uga.edu/people/faculty/xyao/Workshop2007/