A X(i), A Y(i), A Az(i), X/3(i) being respectively the corrections of X, Y, azi 
muth and scale in the model of i order of the strip and n the number of models 
less one. 
The number of order of the first model of the strip is considered to be O. 
The calculation of each point is then made in two operations: first is the atjustment 
(transformation of the autograph coordinates of the points of each model by means 
of a conformal transformation of parameters A X (t), A Y(f), A f3(i) and A Az(i)] 
and after the transformation into ground coordinates, inverse of that effectuated 
with the initial Helmert. 
2.2.2 —STRIPS WITH ONE OR TWO INTERMEDIARY CONTROL POINTS 
When the strips have an intermediary control, the adjustment of X and Y is made 
by means of a 2 nd degree expression; when they have two intermediary controls, 
by means of a 3 d degree expression. 
The expressions to be utilised are respectively: 
f Cx = a 2 X p +a y X p + (d 2 X p 2 + d y Xp) Y p 
[Cy = b 2 X p +6, X p +(c 2 X/ + c X p ) Y p 
and: 
Cx = u R X p 3 + <x 2 X 2 + u y X^ + (¿¿ ;{ XP 3 + d, X p “ + d y XY^ 
Cy = b 3 X 3 + b 2 X* + a 1 X h + (c, A, 3 + c 2 X* + c t X p ) Y 
where for each point: 
X p = X-Xo 
Y„ = Y-Yo 
p 
Xo being the coordinate X of the first central pass point and Yo the coordinate Y 
of the axis of the strip which is considered as the polygon defined by the central 
pass points. 
The determination of the parameters of the adjustment expressions is made as 
follows: 
1 — The coordinates of the control points are transformed by means of a Helmert 
transformation based on the points of the first model of the strip. 
Let X’, Y’ be the transformed coordinates. 
The correction in each control point will be: 
Cx = X’-X 
Cy=Y’ -Y