Image Processing Reference
In-Depth Information
The cities today are spreading into their surrounding landscapes, sucking food,
energy, water and resources from the natural environment, without taking into due
account the social, economic and environmental consequences generated at all levels by
their 'urban footprints'. The urban environment itself is profoundly changing the entire
global ecosystem. Environmental changes are also expressed in land-use changes.
Social, economic or political trends are conveyed spatially. In recent decades, the stron-
gest per capita growth shifted to the more rural areas of the urban fringe (Bugliarello
2003
). Open spaces are increasingly included between cities,
villages, and traffic axes. An urbanizing landscape, accompa-
nying technical infrastructure, and uncontrolled dynamics of
urban growth patterns are the results. The conversion from
land cover to land being used progresses, i.e., predominantly
agricultural surfaces are transformed into settlement and traf-
fic surfaces, resulting in decreased settlement density,
increased traffic, and costly infrastructure development.
Especially the increase of imperviousness at the expense of
the decrease of green and open spaces must be documented
from local to global scale, and it is a 'must' that the knowl-
edge is integrated into climate change investigations and
further global change issues. Socio-spatial patterns are
expressed in different building activities for single family
houses of different strata, with different amounts of green
spaces, shopping facilities and infrastructure have driven settlement areas to further
expand. The settlement density and, correspondingly, the inner urban densification
continue to decrease.
Merely characterizing and monitoring land-cover and land-use change is of
limited use in understanding the development pathways of cities and their resilience
to outside stressors (Longley
2002
). Geological, ecological, climatic, social, and
political data are also necessary to describe the developmental history of an urban
center and understand its ecological functioning (Grimm et al.
2000
). It is the pro-
cess of urbanization that must be described, monitored, and even simulated on
different scales. Dependent on the issue to be investigated upon, the relevant scale
must be selected (see Fig
1.2
). Local and regional environmental effects must be
documented, analysed, evaluated, and, if possible, predicted. Without researchers
and stakeholders exchanging and collaborating, the goal cannot be achieved.
In recent years 'Urban Remote Sensing' (URS) has proved to be a useful tool for
cross-scale urban planning and urban ecological research. Remote sensing in urban
areas is by nature defined as the measurement of surface radiance and properties con-
nected to the land cover and land use in cities. Today, data from earth observation sys-
tems are available, geocoded, and present an opportunity to collect information relevant
to urban and periurban environments at various spatial, temporal, and spectral scales.
The urban pattern causes deterioration in air quality, the urban ecosystem
processes and biodiversity. In this context URS is a necessary prerequisite to
examine how urban forms modify the landscape as a complex system. It can help
to detect and evaluate the distribution of impervious or, likewise, sealed surfaces,
a key parameter of urban ecology (surface and groundwater availability and runoff,
cities today are
spawling into
their surrounding
landscapes,
without taking
into due account
the social,
economic and
environmental
consequences
generated by
their 'urban
footprints'
