Databases Reference
In-Depth Information
newly determined. Imai and Kameda
8)
propose generalized algorithms for train
maps, etc. We here outline these algorithms and show some computational results.
The unified approach for the GFLP problem in
12)
consists of the following three
steps.
1.
Determining a finite set of candidate places for the label to each feature
(feature is either a point or an edge)
2.
Define the cost of each candidate place.
3.
Find a minimum-cost set of candidate places, at most one for each feature,
which do not intersect each other.
Figure 11: Candidate
places of a label for an
edge (vertical division
case)
Figure 12: Candidate
places of a label for an
edge (horizontal division
case)
Figure 13: Costs of
candidate places of a
label for an edge
In order to apply this general framework, we have to determine how to design
candidate places for each label, and further how to set the cost of each candidate
place. Imai and Kameda's approach
8)
works as follows. Suppose that an edge is
given as a line segment. For simplicity the size of each label is fixed. Denoting the
width and height of an edge by
W
and
H,
we compare the slope
s
of the edge with
H/W
, and when
we divide by vertical lines of interval
W;
otherwise by horizontal lines of interval
H,
so that a label position incident to the edge is considered as candidate places, as
in Fig.11 and Fig.12, respectively. Candidate places intersecting with other edges
are deleted. This extends the method in
11)
.
