[X,Y]=meshgrid(x,y) makes a grid where all the x values are the same across the grid, and likewise for yhe y values.
You can fix it by making your own X and Y instead of using meshgrid.
Nx=41; Ny=9;
dx=1; dy=1; %adjust as desired
x=((0:Nx-1)-(Nx-1)/2)*dx; y=((0:Ny-1)-(Ny-1)/2)*dy;
[X,Y]=meshgrid(x,y); %initial approximation
Z1=X+2*Y;
subplot(211); surf(X,Y,Z1);
xlabel('X'); ylabel('Y'); axis equal; view(0,90)
%next: adjust the grid Y-values
Yadj=Y;
for i=1:Nx
if i<=5||i>=37
ymult=1;
elseif i>=32
ymult=(i-25)/12;
elseif i<=10
ymult=(17-i)/12;
else
ymult=0.5;
end
Yadj(:,i)=ymult*Y(:,i);
end
subplot(212); surf(X,Yadj,Z1);
xlabel('X'); ylabel('Yadj'); axis equal; view(0,90)
It works. The code to adjust the y-values is not very elegant, but it demonstrates the possibilities for creating a non-retangular grid.
