JiscMail Logo
Email discussion lists for the UK Education and Research communities

Help for SPACESYNTAX Archives


SPACESYNTAX Archives

SPACESYNTAX Archives


SPACESYNTAX@JISCMAIL.AC.UK


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

SPACESYNTAX Home

SPACESYNTAX Home

SPACESYNTAX  2001

SPACESYNTAX 2001

Options

Subscribe or Unsubscribe

Subscribe or Unsubscribe

Log In

Log In

Get Password

Get Password

Subject:

Re: scaling observed pedestrian flows to an area total

From:

"Read, S.A." <[log in to unmask]>

Reply-To:

Read, S.A.

Date:

Fri, 7 Dec 2001 10:26:23 +0100

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (107 lines)

 Andrew

My research suggests - see papers in vol 1 and 3 of first symposium - that
total public space population of areas corretates very nicely with average
int3 value of the area, so long as the functional makeup of the area is
consistently residential (and low-rise - they are mostly in Holland). The
correlation starts to break down when commercial city centre areas are
included. I controlled this result in Amsterdam by trying to correlate
building and (resident) population densities with public space population.
There was no correlation.

I would suggest that you need to take a good number and range of samples -
physically counting public space populations and testing your proposal,
finding what causes variations and consistensies.

Stephen

-----Original Message-----
From: Juan Alayo
To: [log in to unmask]
Sent: 06/12/01 18:11
Subject: Re: scaling observed pedestrian flows to an area total

Andrew,

If you plan to model the whole of London I can see at least one issue
that
you may want to consider further: the implications of very different
densities in different areas of London.

With regards to the absolute amount of movement in an area, there is an
obvious link to the amount of development (density) in that area, as
well
as the type of land use.  Basically a sq.km. of high density commercial
development generates a lot more journeys than a sq.km. of low density
residential development.

A secondary effect of density is that it actually encourages a higher
percentage of the journeys to be made on foot (since there are more
potential destinations within sensible walking distance).

In London, gross densities (i.e. sq.m. of building floorplate per sq.m.
of
land) vary greatly, from about 3.5 in the City to less than 0.5 for much
of
Outer London.  However, the length of street network per sq.km. does not
vary that much, being about 27 km per sq.km. for the City and around 24
for
areas south of the Thames (Southwark, Lambeth), that have much lower
densities.

What this means is that the City of London may well present levels of
pedestrian movement per km of network more than 10 times higher
(probably a
lot more) than suburban residential areas, only because of the
differences
in density and type of land use (regardless of spatial configuration,
since
they could conceivably have the same street layout).

This would suggest that a model that only considers morphological
properties cannot account for such diversity (unless density was also
very
closely correlated to integration, which Canary Wharf would seem to
contradict).  Space Syntax types of models can give some idea of how
pedestrian flows are distributed throughout an area in a relative rather
than absolute way.  And my understanding is that they tend to give
better
correlations the more homogeneous an area is, and using local
integration
measures rather than global ones (although I may be wrong on this and
someone from Space Syntax could comment).

Therefore, I cannot see that a single model for the whole of London
would
give you a sensible approximation to overall levels of walking, without
doing something about the density issue.

One way round this problem would be splitting the analysis into a number
of
zones (probably very many), that have a certain degree of uniformity.
Establish correlations for each zone (for which the correlation
equation,
slope and intercept, would be different) and then aggregate the various
areas.  The problem then is, how do you select the different zones and
how
many you go for.  If you decided on a size in the region of 2 sq.km. you
might end up with about 1,000 zones.  But even if you decided to choose
a
fraction of that, say 200 zones, you would still need a good number of
survey locations for each, covering the spectrum of integration values.
I
would guess that you might want at least 50 (possibly more), which would
result in 10,000 survey locations.

A different (and perhaps more logical) approach would be to incorporate
land use and density within the modelling tool, which is something I
have
been working on.  With this, you could produce indicators for absolute
accessibility that could compare across the whole of London.  The issue
here is that you would need detailed land use data to incorporate into
the
model for the whole of London, but one would hope that the various local
authorities would be able to provide much of it.

I look forward to hearing further comments on this.  Regards,
Juan

Top of Message | Previous Page | Permalink

JiscMail Tools


RSS Feeds and Sharing


Advanced Options


Archives

September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
2006
2005
2004
2003
2002
2001
2000
1999
1998


JiscMail is a Jisc service.

View our service policies at https://www.jiscmail.ac.uk/policyandsecurity/ and Jisc's privacy policy at https://www.jisc.ac.uk/website/privacy-notice

Secured by F-Secure Anti-Virus CataList Email List Search Powered by the LISTSERV Email List Manager