hsp = surf(x1,y1,zeros(length(x1)));
rotate(hsp,[1,0,0],90)
rotate(hsp,[0,0,1],40)
xd = get(hsp,'XData');
yd = get(hsp,'YData');
zd = get(hsp,'ZData');
a=xd(1:5,:);
b=a(1,2:801)-a(1,1:800); % we know the distnace between 2 points to have a plan with the required angle between the x axis.  
xd1=0:b(1,1):23000;  % then we are extending it so thta it starts at 0 
xd1=ones(1201,1)*xd1;
a2=yd(1:5,:);
c=a2(1,2:801)-a2(1,1:800);
yd1=ones(1201,1)*yd1;