6.2 The Ecological Environment and Urban Morphology
In this section, with respect to the urban morphology (specifically, the density and
urban area shape) regarded as the ideal in the urban model for a compact city, (1) we
will assess what forms existing cities around the world have. Next, (2) we will gauge
what sort of correlation those forms have with the ecological environment, before
going on to discuss the ecological environmental elements that urban planners ought
to be taking into consideration, in order to affect a review of the compact city model.
Specifically, first with respect to (1), we define the urban area of a city not as its
urban districts or artificially developed lands but rather on the basis of its population
density, treating an area with a continuous density mesh of 2000 people or more per
kilometer square to be one urban area unit. We then selected two indicators for
degree of compactness, using each to calculate two degrees. Next with respect to (2),
we first measured a number of ecological environmental values for the urban area of
each city, including its annual rainfall, average temperatures, and average topographical gradient. We then used the degree of compactness measurement indicators
from (1) to produce response variables, and then using a multiple regression model
taking the ecological environmental indicators as explanatory variables, we determined the correlation between the degree of compactness and the ecological environment for each city. We will further discuss the meaning of this correlation. The
cities analyzed were cities with more than four million people and included megacities with a population of greater than ten million. The reason we chose to analyze
cities with more than four million people was because these cities have a set of
similarities that is different to the set of similarities found in cities below that
threshold.
Population density inside an urban area and the variance for that density are
broadly proportional to a logarithm value of the size of the urban area population. In
cities with more than four million people, however, we found that density and its
variance remain at high levels (see Appendix). As cities having large populations,
and which by nature are similar to cities with more than ten million people, we
therefore included cities with more than four million people and up to ten million
people in our analysis.
6.2.1 Measuring the Degree of Compactness
6.2.1.1 Indicators for Measuring City Degree of Compactness
A range of indicators have been proposed for evaluating an urban area’s pattern of
expansion. These include a number of indicators for measuring a city’s degree of
compactness, and of those indicators, Angel et al. (2010) have reviewed
10 nondimensional indicators. When measuring the degree of compactness of an
urban area’s pattern of expansion, the indicator to be used will vary depending on
6 Generation of Urban Morphologies Through Long-Term Evolution of. . .
109
In this section, with respect to the urban morphology (specifically, the density and
urban area shape) regarded as the ideal in the urban model for a compact city, (1) we
will assess what forms existing cities around the world have. Next, (2) we will gauge
what sort of correlation those forms have with the ecological environment, before
going on to discuss the ecological environmental elements that urban planners ought
to be taking into consideration, in order to affect a review of the compact city model.
Specifically, first with respect to (1), we define the urban area of a city not as its
urban districts or artificially developed lands but rather on the basis of its population
density, treating an area with a continuous density mesh of 2000 people or more per
kilometer square to be one urban area unit. We then selected two indicators for
degree of compactness, using each to calculate two degrees. Next with respect to (2),
we first measured a number of ecological environmental values for the urban area of
each city, including its annual rainfall, average temperatures, and average topographical gradient. We then used the degree of compactness measurement indicators
from (1) to produce response variables, and then using a multiple regression model
taking the ecological environmental indicators as explanatory variables, we determined the correlation between the degree of compactness and the ecological environment for each city. We will further discuss the meaning of this correlation. The
cities analyzed were cities with more than four million people and included megacities with a population of greater than ten million. The reason we chose to analyze
cities with more than four million people was because these cities have a set of
similarities that is different to the set of similarities found in cities below that
threshold.
Population density inside an urban area and the variance for that density are
broadly proportional to a logarithm value of the size of the urban area population. In
cities with more than four million people, however, we found that density and its
variance remain at high levels (see Appendix). As cities having large populations,
and which by nature are similar to cities with more than ten million people, we
therefore included cities with more than four million people and up to ten million
people in our analysis.
6.2.1 Measuring the Degree of Compactness
6.2.1.1 Indicators for Measuring City Degree of Compactness
A range of indicators have been proposed for evaluating an urban area’s pattern of
expansion. These include a number of indicators for measuring a city’s degree of
compactness, and of those indicators, Angel et al. (2010) have reviewed
10 nondimensional indicators. When measuring the degree of compactness of an
urban area’s pattern of expansion, the indicator to be used will vary depending on
6 Generation of Urban Morphologies Through Long-Term Evolution of. . .
109