Geography Reference
In-Depth Information
Fig. 1 (a) Original ground plans of selected buildings,
A
—Petronas Towers,
B
—Lund University,
C
—Houses of Parliament,
D
—St. Maurice, (b) Preview of selected generalization levels with
simplification tolerance t
¼
4, 15, 30, 50, 100, 200, 320 and 400 m
300, 320, 350, 400 and 500 m. These steps were selected in order to cover all the
process of polygon simplification—from the most complex to the point in which
greater simplification tolerance would not cause any further change of a shape and
resulted into a rectangular shape of buildings. Preview of selected generalization
steps is shown in Fig.
1b
.
Lastly, 15 shape metrics were calculated (Table
1
), basic shape metrics (shape
area and length) were automatically calculated during the generalization process,
Perimeter-area index and Fractal dimension index were calculated separately out-
side GIS. For other shape metrics, Shape Metrics Toolbox for ESRI ArcGIS for
Desktop (Parent
2014
) was used. Basic description of used shape metrics is in
Table
1
. In this case study normalized versions of shape metrics from the Shape
Metrics Toolbox were used as they are not affected by a shape area. Metrics were
normalized using the Equal Area Circle (Parent
2014
). For more details about shape
metrics, see Parent (
2014
), McGarigal (
2013
), Mesev (
2007
) or Forman (
1995
).
Shape metrics were calculated for buildings
ground plans in every particular level
'
of generalization.
Normalized shape metrics values range between 0 and 1. According to Angel
et al. (
2010
), a circle is the most compact (or ideal) shape possible for a given area.
The higher the value, the more compact the shape. Values equal to 1 indicates that
the shape is a circle. In our case, the finite shape of the generalization is the
