In my work, which is building upon spatial movement work undertaken by
IVT at ETHZ, a critical factor in movement in the city is that it is
not random. People have purpose and destination. They have certain
spheres of influence within the city. Thus there is a set of people
within any area who have purpose within that area, but may come from
I see what you say below in your response to Hans, but how do we
translate the random generation to the purposeful use of a "world"
network with destinations, where we are trying to understand the
average overall purposeful behavior, as against average random behavior?
Maybe. if there is a misunderstanding, it is because I am not an ABM
On 17/11/2009, at 9:13 PM, Bin Jiang wrote:
> Many thanks Hans for the detailed comments, my feedback to which is
> as follows:
> Skov-Petersen wrote:
>> Hi Bin,
>> A few comments/questions:
>> 1) Apparently you are using two sw products: ArcGIS (for G�vle)
>> and NetLogo (for London). Ir is not clear to me how the two were
>> applied. I would assume that NetLogo was used for the agent
>> simulation while ArcGIS was used for network analysis (metrics),
>> but as it reads boh programmes were used for both purposes (but in
>> different regions). Can you clear me up?
> In the paper we just say a few words of the difference between the
> two platforms. At the beginning, we put Gävle data in ArcGIS, while
> London data in NetLogo. However, this is NOT essential. In other
> words, to get the statistics there is no difference between the two,
> but they do differ if visualization is concerned. Obviously in this
> connection, NetLogo outperforms.
>> 2) Is the NetLogo model-code you used for agents interaction with
>> the network publicly available?
>> 3) are your purposely agents (II) applying a 'shortest path' search
>> towards their target?
> Yes, but shortest path can be computed in real time. It would reduce
> the simulation speed significantly.
>> 4) Wouldn't you assume that the purposely agents (II) could be
>> further 'improved' by taking the probability (i.e. the number of
>> potential facilities) into account when selecting targets/
>> destinations as a probability weight 't application of a temporal
>> dimension be considered. As it is, the simulation mimics the
>> behaviour of taxies quite well (roaming short distance, any where,
>> all during the day), but not the way e.g. home-work journeys will
>> take place.
> Of course as long as one has all these locations of potential
> facilities. In our experiments, the destinations are randomly
> generated, and they are randomly distributed.
>> 5) One main finding - as I read it - is that ABM's are not required
>> to simulate traffic flows (which is quite disappointing for an abm-
>> modeler :-)).
> What do you mean by this point? We relied on ABM for simulating
> traffic flows as you can see.
>> Nevertheless, your conclude that abm's provide us with new ways to
>> study the rational behind human (spatial) behaviour, but do not
>> further elaborate on this.
> My point here is that drawn from our experiments ABMs provide a
> means to study human spatial behavior instead of observing from the
> real world.
>> To me - and that is probably what you are saying - the thing is
>> that the network (obviously) is the mandatory, bounding condition
>> for transport behaviour. It is interesting (and efficient) to come
>> up with indicators (metrics) that can predict human behaviour
>> patterns (at a gross level), but that we need the agent-based
>> approach to further enhance our behavioural understanding,
>> especially when considering behaviour beyond the 'average being'.
> No, this is not what I intended to say. Also see above point. My
> focus is understand average being rather than individual being.
>> >>> Bin Jiang <[log in to unmask]> 11-06-2008 17:00 >>>
>> Hi, this paper might be of interest to space syntax researchers
>> any comments are very welcome.
> Bin Jiang
> Division of Geomatics, KTH Research School
> Department 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://fromto.hig.se/~bjg/
> European Associate Editor
> Computers, Environment and Urban Systems: An International Journal
> NordGISci: http://fromto.hig.se/~bjg/NordGISci/
> ICA Commission: http://fromto.hig.se/~bjg/ica/