Geology Reference
In-Depth Information
3.4.2.2
Greedy Triangulation
A triangulation method suitable for use by hand as well as by computer is known as “greedy”
triangulation (Watson and Philip 1984; Jones and Nelson 1992). The criterion is that the
edge selected is the shortest line between vertices. No candidate edge is included if there
is a shorter candidate edge that would intersect it (Jones and Nelson 1992). Figure 3.8a
shows a network of candidate edges with the longer edges dashed. The TIN produced by
this method is shown in Fig. 3.8b. This method is both logical and convenient for use by
hand and is the approach generally used in this topic as the first step in the interpretation.
Fig. 3.7.
Nearest neighbors in a TIN network.
a
Possible nearest neighbors connected by
dashed lines
.
b
Four potential neighbor points
a
-
d
. The
solid circle
includes three points (
a
-
c
) that define a Delauney
nearest-neighbor triangle (
heavy lines
). The
dashed circle
through
a
,
b
, and
d
includes one point in-
side the circle
Fig. 3.8.
Greedy triangulation.
a
Alternative nearest neighbors. Longer edges
dashed
.
b
Longer edges
removed to define nearest neighbors
