Image Processing Reference
In-Depth Information
Fig. 6.7 V-I-S transitions from arid landscapes to various urban features
The V-I-S model serves all of these. For example in urban
morphology it is recognized that the basic building block
is the pixel. However, determination of the composition
of a single pixel is usually of little value in and of itself.
It is the aggregation of multiple adjacent pixels of similar
composition that make ecological analysis possible. The
logic by which pixels are grouped into spatial units
depends on the objective of investigation. Aggregating
similar pixels, or sub-pixel characteristics, into a polygon
creates an “eco-unit” (Ridd 1995 ), an ecologically signifi-
cant landscape unit emphasizing the biophysical character
as derived from the V-I-S composition. The eco-unit may represent a “community”
as in classical ecology. The central business district (CBD) of a large city is a kind
of community or eco-unit dominated by impervious surfaces. Within the CBD there
may be a city park or other anomalies quite different from the general character of
the unit. Outside the CBD residential eco-units may range from high density to
low density and on to surrounding landscapes - each as part of the morphology of
the urban/peri-urban region. Based on V-I-S, the composition may be monitored
for change and modeled for predictive growth and change over time. Urban
morphology becomes the foundation for effective biophysical system and human
system analysis.
the V-I-S
“eco-unit” refers
to an ecologically
landscape unit
emphasizing the
character as
derived from the
V-I-S composition
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