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Stefan Fina Patterns of Urban Sprawl Geographical Analysis
1. Point locations for functions:
Extract locations for residential (grey
points), business/industrial (B) and
public (P) functions. Feature weights
can be applied, i.e. number of people,
number of households (if available).
2. Routing for closest functions
Iterate through all residential entities
(R) and find the nearest business (B,
first leg) and public services entities
(B, second leg). The third leg is the
connection between the B and P
destinations of each residential unit.
3. Aggregation of FT
Feature weights are applied to all
FT distances. Values are then
summed up for each reporting unit
and divided by the number of
entities in that unit.
The formula is:
=
∑
⃗ ( ⃗)
⃗
()
with
r = residential entities,
b = business entities,
p = public services,
i= number of entities
ic = closest entity to i
fw = feature weight
Figure 3. Workflow for geodata processing and calculation of the Functional Triangle (arial photographs from
the Ministry of the Environment of the State of Baden-Württmeberg, road network from GeoStreet+, infas
Geodaten GmbH).
Test cases for FT were conducted with the same data and study area as for DI, using population-
weighted building types from the cadastral database of the State of Baden-Württemberg. The initial
findings indicate that
- FT produces a good overview about the neighborhood mix of land uses in a study area. It can be
used for any study area, and since it is a simple distance measurement, it is easy to interpret and to
communicate.
- When used with population or household weightings, the FT combines pattern information about
urban configurations with density information. With the result being an average distance, feature
weightings reflect the density information in the final value.
- FT can be measured for the current state of the neighborhood mix of land uses as well as for trend
analysis. Any new (residential) development of urban entities will immediately have an impact on
distance calculations.
At the current state of development of the FT, limitations and challenges that can be foreseen are:
- The measurement of interactions between urban entities with nearest neighbor connections is to a
large degree hypothetical. Although one could expect that the distance to business opportunities
and services play an important role in terms of the impact characteristics attributed to sprawl, this
(2)