use surf() to plot a circle from a rectangle matrix

Hey everybody,

I have a greyscale picture and i want to surface plot just a circle from it.

I tried to cut out the circle and plot it with surf(). It didnt work.

After that, i tried to assign NaN to the values i dont want to plot. But they are plotted as zeros. I didnt find a way to ignore those values.

i attached the picture file i am using.

What am i doing wrong?

Im a real Matlab beginner by the way.

Answer 1

[Cris LaPierre]

Sure. See this StackExchange post about exactly this. I'm copying the code below

[x, y] = ndgrid(linspace(-1,1,500));
z = cos(2*pi*(x+y)*2);
z(x.^2+y.^2>1) = NaN; %// remove values outside unit circle
surf(x,y,z,'edgecolor','none')
colorbar
view(2)
axis equal

view(2) creates a top down view.

view(3) creates a 3d view

Answer 2

[Image Analyst]

Maybe you'd like MeshCanopy: MathWorkshttps://www.mathworks.com/matlabcentral/fileexchange/29485-meshcanopy