82 
Ground control used, Massif Central (ITC) 
■ = height point 
A = planimetric point 
Diagram 1 
Transformation of the strip-coordinates into the ground system: a linear, spatial, 
transformation of the strip-coordinates, together with a curvature correction of the 
strip, was executed in the Zebra. 
This curvature correction was designed so as to correct for the influence of the 
earth-curvature in the direction perpendicular to the flight direction, and to correct 
for the combined effect of earth-curvature and (part of) the accumulation of — and 
height — errors in the direction of flight [2]. 
For this purpose (linear transformation together with the curvature correction), 
two planimetric ground control points and four height control points were required 
for each strip (see diagram No. 2). As the required planimetric control was available 
{A ■ ' " 
Diagram 2 
in the strips 1, 4, 5 and 8 only, for strip 2 two points at the extremes of the lateral 
overlap with strip 1 were used, the ground-coordinates of which were obtained by 
the transformation of strip 1 into the ground system, etc. 
Adjustment: With the transformed coordinates, thus obtained, a block-adjust 
ment according to the I.T.C.-Jerie method was to be executed.