77 
In addition, the identification of the following points was questionable (I.Q.): 
7, 8, 10, 15, 31, 46, 48, 53, 73, 84, 87, 90, 104, 107, 108, 118, 119, 225, 227, 231,236, 
239, 240, 242, 246, 255, 273, 274, 277, 282, 283, 284, 288, 289, 294. A few of these 
I.Q. points were common to more than one strip, which allowed a comparison between 
their adjusted coordinates and elevations. In the cases where the compared values 
were reasonably close, the coordinates and elevations were reported to the Presidency. 
The following points were reported to the Presidency with the remark « I.Q. »: 53, 
73, 84, 90, 119, 107 (elevation only) and 108 (elevation only). The other I.Q. 
points were not reported. 
After the test has been completed, the Presidency declared that the following 
points have to be disregarded: 11, 12, 26, 83, 99, 174, 199, 209, 236, 249, 270, 282, 
294, 300. 
Thus, out of the original 295 test points, 66 points had to be excluded for some 
reason or another, and the test had to be conducted on 229 points only. 
Aside from the difficulties concerning point identification, another type of diffi 
culty was encountered in the process of relative orientation. For some reason, possibly 
irregular film shrinkage in the film diapositives, some want of correspondence (some 
time as much as 50 g in the plane of the photograph) was observed in several models 
after completing the process of relative orientation on the basis of the six main points 
of the model. This phenomenon was more pronounced in several models in strips 
3 and 4, and the effect was felt in the final results. Repeated relative orientations 
of the models using different sets of main points did not help in this respect. We 
had to make sure, however, that the six pass points in every model were free of pa 
rallax. 
3 — ADJUSTMENT OF THE BLOCK 
The adjustment of the block was done in three successive phases: ]) adjustment 
of the main strips; 2) adjustment of the secondary strips; 3) block adjustment. 
3.1. Adjustment of the main strips (No. 9, 10 and 11). — This was done according 
to the newly developed « Illini Method » in conjunction with an IBM 650 of the Uni 
versity of Illinois. The Illini Method involves a two-stage adjustment for each of 
X, Y, and Z. First an adjustment of the strip is undertaken according to Karara’s 
Cross-Bases Method (see Bibliography, Entry No. 1). The second phase of adjustment 
involves adjusting the residual errors according to Zarzycki’s Interpolation Method 
(see Bibliography, Entry No. 2). 
At the time the adjustment was undertaken, only the first phase of the Illini 
Method was programmed and handled on IBM 650. The second phase was done gra 
phically. In the meantime, an IBM 7090 program for the Illini Method as a unit 
has been developed, and is now operational. 
3.2. Adjustment of the Secondary Strips: (No. 1 through 8). — The adjustment 
of the secondary strips was done according to the Illini Method as described in pa 
ragraph 3.1. on the basis of photogrammetric control obtained from the main strips. 
3.3. Block Adjustment. — This was done according to the well-known Zeller’s 
Method (see Bibliography, Entry No. 3). In this method, the coordinates and eleva 
tions of tie points are compared in adjacent strips in profiles transverse to the direction 
of the secondary strips. We used 18 profiles, spanning the block. Based on the discre