On Fri, 3 Mar 2006 15:46:36 -0000, Alan Penn <[log in to unmask]> wrote:
>The basics of all this is in Hillier & Hanson, The Social Logic of Space,
>CUP, 1984. look specifically at Ch 3. but you should probably read the
whole
>book if you are interested in spatial analysis.
>
Well, I have answered enough questions on this list –it’s now my turn to
ask some.
What are the SS graduate students being taught these days? That the SLoS
is a book on spatial analysis? That SS is about studying spatial networks?
Does anyone at space syntax know what these things are??? Have any of the
graduate students ever cared to do a search for ‘spatial analysis’ in
google or amazon???
Rui
>Oh, and I thought it was you that asked us not to ignore this
request... :-)
>
>Alan
>
>
>> Dear Alan,
>>
>> Could you be as kind as to send us a published (journal) reference which
>> points this out.
>>
>> You see, we've all read enough emails by now.
>>
>> Thank you
>>
>> > -----Original Message-----
>> > From: [log in to unmask] [mailto:[log in to unmask]]
On
>> > Behalf Of Alan Penn
>> > Sent: 03 March 2006 14:53
>> > To: [log in to unmask]
>> > Subject: Re: [SPACESYNTAX] NOT ignore please
>> >
>> > Its funny isn't it? I wonder why people have trouble with this one.
>> >
>> > The RA equation puts mean depth onto a 1-0 scale between the deepest
and
>> the
>> > shallowest you could possibly have given that number of nodes in the
>> graph.
>> > This is a normalisation.
>> >
>> > The RRA equation then relativisies this as compared to the mean depth
of
>> a
>> > diamond shaped structure with the given number of nodes. This is an
>> > empirical relativisation ie. not particularly 'theory driven' in that
it
>> > works statistically in removing the effects of number of nodes in
urban
>> > axial graphs from the average mean depth in a system. There are many
>> other
>> > ways that this could be done, and since there is no pre-existing
>> theoretical
>> > assumption built into this process nothing is lost by ding it a
>> different
>> > way. However, it does allow you to compare some properties of graphs
>> between
>> > maps of different sizes on a more or less comparable basis. Something
>> you
>> > certainly cannot do for the unrelativised RA values.
>> >
>> > Alan
>> >
>> >
>> > >
>> > > On 03/03/06, Bin Jiang <[log in to unmask]> wrote:
>> > > > Usually we compare space syntax measures within a same system, not
>> > > > across different systems. This is my perception. Am I wrong?
>> > >
>> > > Well, if you use local integration for a single axial map you *are*
>> > > comparing different systems because the number of nodes involved to
>> > > calculate this measure vary for each node. It is the same if you
>> > > compare global integration between different maps.
>> > >
>> > > Therefore, if you do not agree that RRA / Diamond Shapes provides
some
>> > > help... forget the whole thing about local integration... just does
>> > > not work.
>> > >
>> > > For me it is quite OK.
>> > >
>> > > > I am not convinced by the popular saying that the local
integration
>> is
>> a
>> > > > good indicator of pedestrian or vehicle flows. Recently I happened
>> to
>> > > > get some vehicle observation datasets with pressure-sensed
>> techniques
>> > > > (so must be very precise observation). I compared the datasets
with
>> > > > local integration, and did not end up with a good correlation (R
>> square
>> > > > value about 0.5).
>> > >
>> > > I have got the same in this paper:
>> > > "Continuity lines: aggregating axial lines to predict vehicular
>> > > movement patterns"
>> > > http://www.mindwalk.com.br/papers/
>> > >
>> > > That is a problem. I produced a continuity map that reveals clearly
>> > > the main street system of my city (Recife, Brazil). But ...
correlate
>> > > abstract graph properties with real movement is another issue. There
>> > > are many other factors, such as attractors, street width, etc.
>> > >
>> > > Therefore, this is just a matter what is the number you accept as a
>> > > good proof that the urban grid itself (ignoring the other factors)
can
>> > > organise movement patterns.
>> > >
>> > > Regards!
>> > > Lucas Figueiredo
>> > >
>> > > CASA - Centre for Advanced Spatial Analysis
>> > > University College London
>> > > 1-19 Torrington Place
>> > > London WC1E 7HB England
>> > > E-mail: [log in to unmask]
>========================================================================
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