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Exploring the patterns of urban growth across 26 European countries 2769
Table 1. Description of employed indicators (for details see the online appendix).
Indicator
dimension
Composition (1) Land
consumption
Indicator Description
(2) Normalised
urban land
consumption
(3) Growth of
urban land
(4) Sealing
degree of urban
land
Pattern (5) Effective
open space
(6) Decline of
effective open
space
Density (8) Urban
density
The ‘land consumption’ (percentage) is measured as the percentage
share of urban (arti cial) land to the total land area. It indicates the
level of urbanisation for a given area. Urban land is classi ed with
CLC codes < 200, except mining (code 131).
The ‘normalised urban land consumption’ (standard deviations)
indicates by how much the land consumption in an area deviates
from the average of all sampled areas. Positive values stand for
land consumption above average, negative values are below
average. The values are normalised by population density to
account for country size and population.
The ‘growth of urban land’ (percentage) is calculated as the annual
growth of urban land (compounding growth from the start of the
observation period). Annual growth rates were calculated for the
approximate year that CORINE satellite images were recorded
(EEA, 2006b).
The ‘sealing degree of urban land’ (percentage) informs about the
amount of sealed surfaces within urban areas. Lower values are
an indication of a spacious and loose urban setting where builtup
areas are interspersed with large amounts of vegetated plots
of land. Higher values indicate a more compact urban form, thus
being less sprawling like than urban areas with a lower percentage
of sealed surfaces.
The ‘effective open space’ indicates the degree of fragmentation
of open spaces and potential habitats. Conceptually, it examines
the amount and structure of open space within an area, where
larger areas are given a higher weighting in the resulting ‘effective
share of open space’ index. This takes into account ecological
considerations that larger habitats are important elements of
conservation strategies (Ackermann and Schweiger, 2008 and the
online appendix).
The ‘decline of effective open space’ (percentage) is calculated as
the percentage change of the measured effective open space values
within an observation period.
(7) Gini index The ‘Gini index’ measures the distribution of new urban areas
across the country. High values indicate that new development
has been concentrated in few places, for example along coasts
or around main hubs. In contrast, low values show that new
settlements are widespread in many places. In the latter case, areawide
land take can be assumed to lead to higher fragmentation
rates of open space.
The ‘urban density’ (inhabitants per hectare) is a widely used
measure to indicate the intensity of urban land use. It was
calculated by a spatial overlay of population and sealed surfaces
on a 100 × 100 m resolution. Generally speaking, the lower the
indicator values, the lower the intensity of land use.
2.2 Data use
The data used for the mapping of urban form patterns in EU countries were sourced mainly
from the CORINE (Coordination of Information on the Environment, CLC) project of the
European Environment Agency and complementary datasets on soil sealing (“FTS Soil
Sealing layer”) and population (“Population density grid of the European Union”), both also
from the European Environment Agency. The CLC land-cover dataset was rst put together