Dear Drew - The key to your question is this. Where environments are
linearly organised, as in an urban street system, and where most
movement is purposeful and point to point rather than exploratory,
then a linear representation of space is by far the best for
capturing movement. Among the linear representation, segment angular
analysis, as available in DepthMap is again the best, as Shinichi and
I showed in our recent paper "Network and Physchological Effects in
Urban Movement'at COSIT05 which, we hope, allows us to distinguish
the effects on movement that come from the network itself and those
that come from how we read the network. If you have not see it I can
send you a copy with colour images.
Visibility graph analysis is is much less good at predicting this
predominantly linear kind of movment, since it conflates the one and
two dimensional extension of space (a point can have a high value
because it is part of a long space, or part of a fat space, or both,
but urban movement doe not in general respond to these equally. Where
visibility graph analysis come into its own - and again by far the
best versions and capabilities (such as intelligibility analysis) are
in DepthMap - is where movement is more exploratory and so exploits
the second dimension of spaces as much as the first. We have found it
works particularly well in department stores, and it can often be
used to clarify patterns of movement in and around public squares,
though in the latter case it is probably best used in conjection with
segment angular analysis.
I believe that Alasdair Turner can best advise you on how to deal
with the 'visible but not permeable' problem, and he will see a copy
of this and I hope respond. In the meantime I will read your paper
with great interest. - Bill
>Hello,
>
>Last year I completed a senior thesis that uses the case study of an
>American college campus to compare space syntax measures of urban
>form with behavioral measures of spatial judgment and memory. I
>found that the global integration of a location on the campus
>predicts students' accuracy at recalling that location when asked
>under controlled conditions. The document is available on-line as a
>PDF, along with a brief summary handout, a demo of the spatial
>judgment and memory tasks, and the axial map that I used:
>
>http://drew.dara-abrams.com/research/
>
>I would appreciate any questions, comments, or suggestions you may have.
>
>I am currently revising this work at University of California, Santa
>Barbara, and readying it for publication. While preparing to run the
>study on this campus, I have been wondering about how to best use
>axial maps and visibility graphs to characterize outdoor settings
>that are not simply open streets and solid buildings. For instance,
>the university campuses that I am considering are filled with
>landscaping as well as roadways, some of which can be walked across
>and some of which cannot be traversed but can be seen across. I am
>planning on doing two sets of models, one that describes spaces that
>are accessible/can be walked across and a second that describes
>spaces that are visible/can be seen. As I am doing this, I am trying
>to assemble some rough guidelines for which physical features to
>ignore and which to include in space syntax models when "ground
>truthing" CAD plans, but I don't want to duplicate work that may
>have been done previously. I would greatly appreciate any literature
>references or other suggestions on methodology.
>
>Thank you for your time,
>Drew Dara-Abrams
>
>--
>
>Drew Dara-Abrams
>University of California, Santa Barbara
>Dept. of Psychology - Cognitive and Perceptual Sciences
>NSF IGERT in Interactive Digital Multimedia
>[log in to unmask]
>http://drew.dara-abrams.com/
>+1 (805) 680-7191 (cell)
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