Yes I think this is the case but in street networks as Roy Wagner pointed
out, then any 3x3 grid is by definition non planar - I cant remember where
I read that j-graphs were planar and I dont intend to search for this but
in my software I was wondering if I should try to unravel the j-graph but I
cant because in general it is non planar
Mike
At 21:13 20/07/2005, you wrote:
>Mike,
>
>Can I amend Alasdair's statement: "However, they do seem to be used
>primarily for graphs of convex spaces connected through adjacency, where the
>graph is planar."
>
>This should be the graph is usually planar, except we often use these convex
>graphs for multi storey buildings where they can become non-planar again.
>They generally will become non planar if there are more than two stair
>cases...
>
>Alan
>
>-----Original Message-----
>Subject: Re: About Space Syntax Measures
>
>Dear Ruth and Mike,
>
>The mail is in the list archives:
>
>http://www.jiscmail.ac.uk/cgi-bin/webadmin?A2=ind0504&L=spacesyntax&P=1563
>
>There is a link to the PDF at the bottom of the page.
>
>As ever in a continually developing field, I doubt there is a single
>"unequivocal set" of measures.
>
>I would agree with you both: I have always assumed that the j-graph is
>simply the graph as viewed from a particular vertex.
>
>However, they do seem to be used primarily for graphs of convex spaces
>connected through adjacency, where the graph is planar.
>
>Alasdair
>
>Ruth Conroy Dalton wrote:
> > Mike,
> >
> > To the best of my knowledge, the j-graphs as used in space syntax as
> > non-planar (as is the road system). I do not believe they can be
> > 'untangled'.
> >
> > With respect to the list of definitions, I am still aiming to set up a
> > space syntax 'wikipedia' which would have definitions in it, however I
> > have made scant progress so far - sorry. I do not recall who sent the
> > original list but I believe Bill posted a pdf of a scan (???).
> >
> >
> > Regards
> > Ruth
> >
> >
> >
> >> I have two queries
> >>
> >> 1. At the recent space syntax conference in delft, someone said that a
> >> list of the measures - integration, depth and so on - had been sent to
> >> the list at some point in the past. What I need is an unequivocal set
> >> of definitions of depth, relative depth, integration and so on. If
> >> someone has this, then could then circulate it again or point me in
> >> the right direction. many thanks
> >>
> >> 2. I seem to recall reading somewhere that the j-graph - ie the
> >> tree/semi-lattice that emanates from any node to all other nodes - was
> >> said to be a planar graph that can be untangled. I am confused by this
> >> as this could only be the case if the original street map were a
> >> planar graph, I think. I am unsure of this. can someone enlighten me.
> >> Thanks again.
> >>
> >> Mike
> >>
> >>
> >> _____________________________________________________________
> >>
> >> Michael Batty, Director, Centre for Advanced Spatial Analysis (CASA) at
> >> University College London, 1-19 Torrington Place, London, WC1E 6BT UK
> >> _____________________________________________________________
> >>
> >> tel 44 (0) 207 679 1781 fax 44 (0) 207 813 2843 mobile 44 (0) 7768 423
> >> 656
> >> Personal web page is at http://www.casa.ucl.ac.uk/people/MikesPage.htm
> >
> >
> >
>
>--
>Alasdair Turner
>Lecturer in Architectural Computing
>Bartlett School of Graduate Studies
>UCL Gower Street LONDON WC1E 6BT
>
>Course Director: MSc Virtual Environments
>MSc Adaptive Architecture and Computation
_____________________________________________________________
Michael Batty, Director, Centre for Advanced Spatial Analysis (CASA) at
University College London, 1-19 Torrington Place, London, WC1E 6BT UK
_____________________________________________________________
tel 44 (0) 207 679 1781 fax 44 (0) 207 813 2843 mobile 44 (0) 7768 423 656
Personal web page is at http://www.casa.ucl.ac.uk/people/MikesPage.htm
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