Let me see... hummm....
the population density on your back garden...
cool :)
Rui
On Sun, 3 Jun 2007 22:31:49 +0100, Alan Penn <[log in to unmask]> wrote:
>Rui, Anzir,
>
>This just shifts the problem from 'what is a street' to 'what is a city' -
>Defining a density threshold might sound attractive as a proposition but
it
>is not as simple as that. Amongst the problems are: 1. 'density of
what?' -
>is it density of residential population, habitable rooms, area of
>floorplate, floor area of buildings? 2. Density is something per unit
area -
>what is the area over which you are measuring? You are suggesting a
density
>threshold as a means of defining a boundary (the built up area of the
city)
>but cities are essentially inhomogeneous over the kind of factors in 1.
i.e.
>at some spatial resolution Regents Park would be considered devoid of
>residential population or buildings and so not part of the city. At a
finer
>scale of resolution so would my back garden or the street in front of my
>house. If I eliminate all of that 'open space' then I am only measuring
the
>building area, but then a single house in the middle of the Sahara would
be
>just as much a city as anything else. To make any sense of this kind of
>thing you need to start with a boundary and then calculate density within
>that. Back to the Italian problem of the administrative boundary including
>functional regions which encompass rural hinterlands....
>
>It is all a bit like the old problem of defining an elephant - 'its large
>and its grey and I know one when I see it'. There is no doubt in my mind
>that Milan and Rome are cities regardless of how they choose to define
their
>administrative boundary. There is also no doubt that density of the built
up
>area is part of that judgement. But there is also no doubt that density by
>itself is not enough and can become circular if you try to use it to
define
>the boundary over which it itself is measured. It may sound simple, but
its
>not..
>
>Alan
>
>>
>> Rui,
>> On 3 Jun 2007, at 11:18, Rui Carvalho wrote:
>>
>> > On Sun, 3 Jun 2007 12:45:11 +0300, Yodan Rofe <[log in to unmask]>
>> > wrote:
>> >
>> >> Oh really?
>> >
>> > Well, I didn't say you would recover cities "as we know them". I
>> > said that
>> > a city could be defined by population density and you would need to
>> > decide
>> > on a threshold.
>> >
>> > Localized population peaks (like the villages you mention) are
>> > obviously
>> > not a city. Of course, you wouldn't recover the boundaries of those
>> > italian cities you mention, but that seems only natural to me.
>>
>> Only cover a city to the edge of its built up area, and do the
>> density count within that. Similarly for the villages...
>>
>> I think you mean to define a "built up area" rather than a city per
>> se. Whether the built up area is small or large is irrelevant if
>> you're going to define a threshold for "built up area". You may also
>> need to have different thresholds in different cultural milieux,
>> where different patterns of "urbanism" have occurred.
>>
>> --
>> Anzir Boodoo MRes MILT Aff. IRO
>> transcience, 72 Staplehurst, BRACKNELL RG12 8DD
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