How do you create a surf plot in cylindrical coordinates?
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In general, the syntax for a surf plot is surf(X,Y,Z). I have u = F(r,z). I'd like to do surface plots of u for multiple cross sections at z = h1, h2, h3, etc. Is there a simple way to create a surf plot in cylindrical coordinates, i.e., something that would be analagous to the syntax: surf(r,phi,u) where u = u(r,h1)?
Jonathan Epperl on 19 Nov 2012
Or even easier, remember that you're not forced to put just one variable X in the first argument of surf, all you need is a parametrization. So in your case, assume you have vectors r and phi. Then make them into a grid, obtain a matrix with z-values using your function F and just plot:
[R PHI] = meshgrid(r,phi);
Z = F(R,PHI); % which assumes your function is vectorized
surf(R.*cos(PHI), R.*sin(PHI), Z);
More Answers (2)
Matt J on 17 Nov 2012
Use TriScatteredInterp to interpolate your data onto a cartesian grid. Then plot using SURF as usual.
Teja Muppirala on 19 Nov 2012
You can use POL2CART to convert the data from r/theta to x/y and then call SURF.
[R,TH] = ndgrid(0:0.1:5,linspace(0,2*pi,41));
F = @(r,th) sin(th).*sinc(1+r);
Z = F(R,TH);
[X,Y] = pol2cart(TH,R);