Note that iterative solutions or some form of recursive partioning were 
used by all participants in this category to solve the normal equations. 
3. Weights 
Choice of weights can influence the results of the adjustment. In the 
sequential procedures weights (as given by those participants reporting use of 
weights) were assigned to ground control points relative to a weight of one for 
tie points between strips. Weights assigned to ground control points, as 
reported by participants 1 and 2, are summarized in Table 3 along with degree 
of equation utilized for the adjustment and number of iterations required for 
convergence. Weight as defined in Table 3 is the value by which the contribu- 
tion of a point to the normal equations is multiplied. ; 
Weights incorporated into simultaneous solutions are generally taken as 
being inversely proportional to the estimated variances of the observed values. 
Factors used by Participants 8, 9, and 10 for weighting their respective simul- 
taneous solutions are tabulated in Table 4. 
D. TEST BLOCK CONTROL CONFIGURATIONS 
  
Control configurations were specified and are illustrated in Figure 1. 
Note that arrays À, B, and C represent near minimum, moderate, and dense amcunts 
of contról respectively. The number of planimetric and height control points 
in these arrays are as follows: 
Planimetric : Vertical 
Array Control Points Control Points 
A 6 : 12 
B 12 22 
26 38 
In general, participants reStricted their tests to the specified arrays A, B 
and C. However in one case, Participant 1 modified array A by adding two 
elevations to the planimetric control points located at the mid-points of the 
sides of the block. This particular array, designated A', is.illustrated in 
Figure 4 and contains 6 planinetric and twelve vertical control points. Results 
from tests with this array are tabulated separately.