hello Mads
like this ?
load('pqfile.MAT')
% remove NaN and correct for size mismatch
A(isnan(A)) = [];
F(isnan(F)) = [];
A = A(3:end);
A(1) = 0; % force first value to 0
% central curve
x1 = [ -A(end:-1:2); A];
y1 = [ -F(end:-1:2); F ;];
% top curve
x_rev = -0.1;
y_rev = interp1(x1,y1,x_rev);
% let's do a strech of x data (linear equation xnew = a x + b)
% for the x data
a = 1 - x_rev/max(A);
b = x_rev;
Atop = a*A + b;
% for the y data
a = 1 - y_rev/max(F);
b = y_rev;
Ftop = a*F + b;
% the bottom curve is the symmetrical of the top curve
Abot = -Atop(end:-1:1);
Fbot = -Ftop(end:-1:1);
plot(x1,y1,'k','linewidth',3);
hold on
plot(Atop,Ftop,'r');
plot(Abot,Fbot,'b');
hold off
