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Anzir, I hadn't realised that you were interested in the small scale network implied by the pedestrian mode - I thought it was more a regional thing. You might like to take a look at that attached paper I gave at the last Space Syntax Symposium in which I developed spatio-temporal maps for urban areas and building interiors. In this paper I develop both single point of origin and all to all representations involving both spatial configuration and time of travel, and show that for a given 'maximum speed' that these are representable on a surface in three dimensions (and so as a contour map if you want). It is however a simple matter to demonstrate that if you allow variable travels speeds that these fill a volume in space time from a single point of origin, and that if you go further to look at all to all interactions these require certain constraints to be representable in a three dimensional volume - for example that travel times are the same in each direction on a trip. Alan Penn Professor of Architectural and Urban Computing The Bartlett School of Graduate Studies University College London Gower Street London WC1E 6BT +44 (0)20 7679 5919 [log in to unmask] www.vr.ucl.ac.uk www.spacesyntax.org > > Noah, > On Tuesday, Nov 30, 2004, at 09:55 Europe/London, Noah Raford wrote: > > > Dear Anzir, > > > > Do you mean an all-point to all-point travel time map? Something > > displaying the average travel time to all points? This sounds similar > > to metric integration, which would of course be focussed on the centre > > of the UK. I think you probably mean something more sophisticated > > though, reflecting the configurational conditions of the road network. > > Someone probably has done something similar but I haven't come across > > it > > myself. Good luck! > > Unfortunately not... this was simply a map of the UK distorted to show > best travel times from London. Something that was more complex or > sophisicated than this would be very difficult for a network where the > travel time on links can vary according to their type or other > characteristics. For example, on rail, Leeds is 2 hours from London by > fastest train, and also 2 hours from Birmingham (which is about half > the distance). > > Such a flat map cannot display such things. A GIS based contour map, > however, would be more suited to displaying that information (I guess > you would have fields with travel time from London, Birmingham, > Manchester, Glasgow, etc. in the dataset and simply draw contour maps > from each. I know this is possibly a little simplistic, but going > beyond this would require the GIS to literally follow the network in > the way the OS' routing plug ins can do (I've used OSCAR before, but > this doesn't give travel times. We were also trying to use it for > calculating walking distances when it's a road based tool, which meant > we couldn't exploit footpaths and alleyways). > -- > Anzir Boodoo MRes MILT Aff. IRO > transcience, Leeds Innovation Centre, 103 Clarendon Road, LEEDS LS2 9DF