On Tue, 9 Jan 2007 17:00:05 -0000, Alain Chiaradia
<[log in to unmask]> wrote:

>Dear Rui
>
>Knowing how well you are aware about the convex space coverage problem, you
>may perhaps entertain us with comments and enlightenments on most transport
>demand models use of region definition, which understood as the modifiable
>area unit problem, sometimes know as the ecological fallacy. Mike as
>published quite a few papers on this while back, it may provide you with a
>much more serious problem to bask on. Another one is perhaps to wonder on
>how transport model define the bound of the model or the network encoding,
>an accepted mess for too long, I agree, what are your thoughts about it?

Alain,

I just gave a seminar here in Dresden to Prof. Helbing's group:
http://tu-dresden.de/die_tu_dresden/fakultaeten/vkw/iwv/tme/studium/hauptseminar/index_html

Mike is giving another seminar this monday -why don't you join us and ask
these fascinating questions yourself to the experts in traffic engineering?

Oh, and Re axial lines, I've written three papers (published on ISI listed
journals) on it, two of which deal with problems related to axial maps -have
you read them?

I trust you are well.


Rui



>
> 
>Alain 
>________________________________________
>
>
>-----Original Message-----
>From: Rui Carvalho 
>Sent: 05 January 2007 10:58
>To: 
>Subject: Re: How to draw Axial map for traffic analysis?
>
>On Fri, 5 Jan 2007 02:54:03 +0000, Chengke LIU <[log in to unmask]> wrote:
>
>>Dear all,
>>
>>I am a master student, currently working on my final dissertation of
>>applying space syntax to traffic analysis. I need to draw an axial map of
>>whole Hong Kong territory. I know that Axial map of London consisting 
>17321
>>lines is successfully done by somebody. 
>>
>>According to the statements made by Hillier and Hanson in 1984, in the 
>book
>>named "The Social Logic of Space", the processing of making an axial map
>>should begin with the longest straight line, then the second longest, and 
>so
>>on until the all convex spaces are covered and all axial lines should
>>intersect with each other without repetition. How could the creator of
>>London axial map ensure this principle when he drew the map? 
>
>The definition in the social logic of space is arbitrary. 
>
>There is no guarantee that covering convex spaces so that axial lines 
>intersect without repetition has anything to do with the way people draw 
>axial maps in practice -in fact, convex spaces seem to have little to do 
>with axial lines or axial maps.
>
>So the answer to your question is: he couldn't.
>
>
>>
>>I know axial line is drawn based on visibility, you can go where you can
>>see. But in my work, I need to analyze the traffic movement in the city's
>>street network. Is that justified to draw the lines based on reachablity?
>>Somewhere in the city, based on visibility, the axial lines should
>>intersect, but based on reachability they should not. For example, please
>>see the attached figure1, the axial line 1 should intersect with axial 
>line
>>2 and 3 from the visibility point of view, but should not because street 1
>>is not directly intersected with street 2 and 3 (Figure 2), in other world
>>car driving on line 1 can not directly shift to line 2 and 3. Which
>>principle should I use, visibility or reachability when I draw the axial 
>map?
>>
>
>Again answers seem to vary: axial lines are straight lines on a map on 
>mondays and tuesdays, but they are traced using visibility on wednesdays, 
>thursdays and fridays.
>
>Look into the archives of this list and you will find people telling you 
>to use both on different occasions.
>
>Rui
>
>
>>Any advice will be highly appreciated!
>>
>>
>========================================================================