20
"7
X
r
i ?
Y
= FT £
Y
.... 4.34
r=l
Z
.Z
3
j
the coordinates of the centroid of sub-block j
the coordinates of any point r in sub-block j
total number of points in sub-block j and used in
the solution
(2) The best-estimate of the coordinates of a point r is taken as the
average of its coordinates from the sub-blocks in which it appears.
Thence:
. . . . 4.35
X
r
x
i M
Y
= FT
Y
i = l
Z
_Z_
= 1, 2 ... M
M = the number of sub-blocks containing the point r
If point r is a ground control point, (X, Y, Z) r will be taken as its
control coordinates rather than the average.
(3) The transformation equation used to minimize the discrepancies between
the coordinates (>T, Y, Z) r , as a best-estimate, and the coordinates
(X, Y, Z)?, as given for point r in sub-block j, is the following:
-i r i r
+ c.
. .. . 4.36
b -a
in which,