Geoscience Reference
In-Depth Information
Table 1 Area profile 1
Elevation
changes (m)
No. of control
points
No. of check
points (1)
No. of check
points (2)
Regional
dimensions
250 × 275
16
123
28
26
Table 2 Area profile 2
Elevation
changes (m)
No. of control
points
No. of check
points (1)
No. of check
points (2)
Regional
dimensions
6
75
18
18
450 × 300
4.6 Triangulation Method
This method deals with the linear interpolation elevations based on Delaunay
triangulation (Zhong et al. 2008 ). Delaunay triangles are formed on raw points,
which have the following features;
• The three corners of a triangle should not be on a curve.
• Two corners of a triangle can be on a curve, but the third corner must be on a
separate curve.
• If a circle passes through the three corners of particular triangle, then it must not
pass through the corresponding triangle's corner, which has a common side.
After the surface reconstruction with Delaunay triangles, the unknown height can
be determined. Each surface equation of a triangle can be specified as follows;
z = ax + by + d
Thus, the height of any point within this level would be:
z cl = ax c + by l + d
The coefficients a, b and d are calculated through the least squares method using
the height of the elevation of the triangle's corners.
5 Data Assessment and Evaluation Criteria
In order to evaluate smart and ordinary interpolation methods, two parts are com-
monly used. Part one is the existing software AutoCAD Civil 2D Land Desktop
2009 and part two is the acquiring data for mapping 1:2000 in Port Khamir, which
is located in Hormozgan State, south of Iran. In both parts, numbers of points are
used as the control points. Other points are considered as the checkpoints that are
grouped in two series of check points and they are called checkpoints (1) and (2).
The characterizations and number of control and two series of check points in both
areas are shown in the Tables 1 and 2 . Using control points and interpolation meth-
ods, the heights of the two series of the checkpoints (1) and (2) are obtained and it
 
Search WWH ::




Custom Search