Dr. Rui Carvalho
Senior Research Fellow
Centre for Advanced Spatial Analysis
University College London
1-19 Torrington Place
London WC1E 6BT, U.K.
From: Alan Penn [mailto:[log in to unmask]]
Sent: 09 June 2007 14:09
To: 'Rui Carvalho'
Cc: 'Bill Hillier'
Subject: RE: What is an axial line?
why are you resending messages to the list that were sent there in the first
place? This is very much against mail list etiquette as it annoys people
having their mail boxes filled up...
> -----Original Message-----
> From: [log in to unmask] [mailto:[log in to unmask]] On
> Behalf Of Rui Carvalho
> Sent: 09 June 2007 13:59
> To: [log in to unmask]
> Subject: Re: What is an axial line?
> Rui Carvalho
> Senior Research Fellow
> Centre for Advanced Spatial Analysis
> University College London
> 1-19 Torrington Place
> Gower Street
> London WC1E 6BT, U.K.
> On Tue, 5 Jun 2007 13:59:24 +0100, Professor Bill Hillier
> <[log in to unmask]> wrote:
> >Rui, in syntax every axial line is drawn with respect to all others,
> >and you can only be sure that any line is a correct one by checking
> >it with reference to the system as a whole. The proper question is:
> >'Are axial graphs unique', that is, is there a correct one for every
> >urban system. I believe we showed two ways in which we could be sure
> >of this in my Rejoinder to Carlo Ratti. At that time - I think on
> >this mailbase - I challenged sceptics to show a case of a settlement
> >where, given that we agreed what was to be mapped, the definitions we
> >offered allowed more than one interpretation of the axial graph. So
> >far we have had no candidates.
> >Anyway, until someone shows that axial graphs as we defined them are
> >not unique, and that there is not a 'correct' graph for each
> >settlement, we can say with reasonable confidence that an axial line
> >is any line that is a member of the set making up a correct axial
> >graph. In all other respects it is just a line drawn on a map.
> >Since we cannot limit its length, connectivity or straightness, which
> >are the only intrinsic properties a line has, it is clear that we can
> >only define axial lines with respect to the system of which they form
> >a part, that is, with respect to the extrinsic, not intrinsic,
> >properties of each line.
> >So if you are interested in the rigour or otherwise of axial mapping,
> >your question seems to be the wrong one. It really should be: Do
> >settlements have unique axial graphs ? To expect to build such a
> >graph from some kind of essentialist definition of a line, however
> >derived, is really a 'reifying slices' error.
> >By the way, I don't like beer. But Portuguese wine is another matter
> >if you have access to a good producer ! - Bill
> >At 11:06 05/06/2007, you wrote:
> >>Free pints for life to the first who can give an unambiguous definition
> >>of "axial line" -and that's out of a post-doc's salary, so you see how
> >>sure I am that this is mission impossible!
> >>C'mon Alan!
> >>Rui Carvalho
> >>Senior Research Fellow
> >>Centre for Advanced Spatial Analysis
> >>University College London
> >>1-19 Torrington Place
> >>Gower Street
> >>London WC1E 6BT, U.K.