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Stefan Fina Patterns of Urban Sprawl Geographical Analysis
where all functions are within the same or in adjacent blocks, distances are small (due to the large size
of the buildings, straight line distances are significantly smaller than network distances). Example 2
shows a small town which has grown in zones around a historic center. Business locations and public
services are separated from residential zones, distances are therefore slightly higher. Example 3 shows
a typical rural setting for Southern Germany: Small villages share a range of service functions, usually
with high levels of commuting and large distances that need to be covered. The last example (4)
depicts the type of urban growth that is most commonly referred to as urban sprawl: A high
segregation of land uses with extensive land consumption for industrial and residential locations,
mostly along major roads and isolated from the city center. Distances that need to be covered are
therefore large.
1: Urban center (high mix of uses, short distances) 2: Small town (some separation of land uses)
3: Rural setting (long distances, sparse road network) 4: Suburban sprawl (high separation of land uses)
Figure 2. Examples of the Functional Triangle calculation(arial photographs from the Ministry of the
Environment of the State of Baden-Württmeberg, road network from GeoStreet+, infas Geodaten GmbH).
The final indicator value is based on the calculation of the average distance for all functional triangles
in a study area. In terms of data it can be computed with any spatial representation of urban entities as
long as they can be differentiated in terms of their function (i.e. households, buildings, land use zones)
and attributed with a meaningful number of trips. Fig. 3 illustrates the workflow for the calculation of
FT: the nominator is calculated through the aggregation of all functional triangles in the study area,
divided by their number (see formula in step 3).