I have done a lot of geostatistics over the lasts three years so I could look into doing something although I wouldn't look at the distorted cartogram since I despise them with a passion :) Also doing it by Postcode centroids would be far too small for our purpose but looking at it at a council boundary level would be better and cuts the amount of work needed to get something useful :)

Seddon

On Fri, Dec 17, 2010 at 8:01 AM, Charles Matthews <charles.r.matthews@ntlworld.com> wrote:

An innocent-enough question on the demographics of WMUK's membership has
led me a merry dance so far. I'm sharing it with this list since it
seems interesting in its own right, and (judging by chat at Sunday's
meetup) someone may well know more than I do about it.

The idea is to start with postcodes, rounded off like CB2, for each
member, and then do a graphical plot. Since the so-called postcode
centroids are well known data, that part isn't hard. But the big urban
areas will not be clearly represented.

The key word here seems to be "cartogram": see WP article. What I really
would like is a "population cartogram", of area type, so a smoothing out
of population density to be more even in a distorted map. There are
examples as Figure 9 and Figure 10 in

http://www.statistics.gov.uk/downloads/theme_population/SMPS58.pdf

Those, though, are not based on postcode areas, but on census data done
by wards.

Anyone (I'm sure we have some experts) on the list who understands the
point here? Locating the postcode centroids within their census ward,
once an for all, (i.e. just some matching that may have been done
already) looks to be enough for the basic purpose of displaying
membership data to find clusters. Alternatively some sort of population
cartogram based on postcode areas could do it. Doesn't look like rocket
science. Locating the postcode centroid by district so that the Figure
10 map of the PDF could be used as a basis could be done with the list
on the next page (p. 24 of document).

Comments, please.

Charles


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