From Fractal Urban Pattern Analysis to Fractal Urban Planning Concepts - Computational Approaches for Urban Environments - page 33

phenomenon to the rather top-down planning strategy in China in opposition to
urban dynamics in Western countries more seen as resulting from self-organization
processes. The discussed empirical results show that weaker planning strategies
tend, too, to generate more uniform patterns, but in Western countries, this
homogeneity is linked to low density, contrarily to Chinese cities. This shows again
that fractal dimension provides different and indeed complementary information
about spatial organization to density.
Indeed, the hierarchy of lacunae, typical of fractals, at the metropolitan scale
saves large zones from urbanization by concentrating urbanization along develop-
ment routes, thus recalling the Northern countries' planning concept. However, the
fractal planning concept goes beyond this, as shown in Fig. 2.11 , where we illustrate
the concept by comparing the Sierpinski carpet already introduced to a scheme
resembling the finger plan. We assume that in both systems the axes correspond
to a transportation network and that urbanization follows these routes.
In both the patterns b and c, the total network lengths are the same. Even if both
the networks follow a radial-concentric logic, the density of network (Fig. 2.11 b)
decreases continuously when moving away from the center. Network (Fig. 2.11 c) is
a Sierpinski gasket which follows the same fractal logic as that of the Sierpinski
carpet of Fig. 2.3 c. It fills space in a diversified and more contrasted way than
network (Fig. 2.11 b). Zones around nodes, even in periphery, are densely covered
by network branches, whereas other zones, of different size, are not served. This
corresponds to the underlying hierarchical organization. Hence, the large square-
like zones on the edges of the figure can be thought of as large natural reserves or
rural areas. As illustrated for the upper left part of scheme (Fig. 2.11 c), these large
zones are connected to smaller squares, so forming a connected spatial system of
green areas penetrating into urbanized zones. These green corridors have the double
function of providing leisure areas close to residential areas and of guaranteeing
good “ventilation” of the city center. But the concept avoids the damaging effects of
landscape fragmentation for biodiversity. It should be emphasized that the scaling
principle of fractals extends the idea of articulating green space and urbanized areas
to a local scale. Indeed, the observed lengthening of urban boundary, one of the
Fig. 2.11 ( a ) The Eberstadt-Möhring-Petersen plan for Berlin (Source: Eberstadt et al. 1910 )and
( b ) a non-fractal axial plan, compared to a fractal one ( c ), both having the same total axis length