London WC1E 6BT, U.K.
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
________________________________________
Rui Carvalho
Senior Research Fellow
Centre for Advanced Spatial Analysis
University College London
1-19 Torrington Place
Gower Street
London WC1E 6BT, U.K.
