Total settlement fragmentation index
SFI = IFI + UFI =
∑ LoΛ+∑ L * ^∑S
Au
(5)
The index gives the indication about the total fragmentation in the spatial unit due to the
combined effects of the infrastructures and linear urbanisation.
|
SFI values_____ |
Environmental fragmentation landscapes |
|
SFI< 0.04 UD<15 mq/ha |
Urban settlement very scattered, with some small |
|
0.04 < SFI < 0.15 15 <UD <40 mq/ha |
Urban settlement very scattered, with some small |
|
0.15 < SFI < 0.31 40 <UD < 100 mq/ha____________ |
Urban settlement scattered again, but with |
|
0.31 < SFI < 1.90 100 <UD < 300 |
Urban settlement mainly aggregated, with urban |
|
SFI > 1.90 UD > 300 mq/ha |
Urban settlement formed by different kinds of |
Figure 11 - Sample of the total settlement fragmentation index (SFI) and its relation with Urban density
(UD) for Umbria region
Conclusion
As we said the presented data should represent a profile on urban landscape condition
that have to communicate with eco-biogeographical data implemented on the same
spatial units. This step can permit to obtain relation functions between the settlement
indices and biodiversity indices.
With regards to the cited indices it is necessary to make some considerations: first of all
it is important to define level and dimension of the “minimal analysis units” (MAU) in
which are realized the observation and the interpretation of the phenomena explain from
the different indices.
Normally, in fact, these MAU are very small when are relative to eco-biogeographical
data, and are instead larger when are relative to urban and territorial data. At this aspect
are link the major problems for implementing the correlation functions.