plot a set of 3D data in different angles in MATLAB
I have a formula that depends on theta and phi (spherical coordinates 0<=theta<=2*pi and 0<=phi<=pi). By inserting each engle, I obtained a quantity. Now I have a set of data for different angles and I need to plot the surface. My data is a 180*360 matrix, so I am not sure if I can use SURF or MESH or PLOT3. The figure should be a surface that include all data and the axes should be in terms 开发者_如何学Goof the quantity, not the quantity versus the angles. How can I plot such a surface?
I see no reason why you cannot use mesh
or surf
to plot such data. Another option I tend to use is that of density plots. You basically display the dependent variable (quantity) as an image and include the independent variables (angles) along the axis, much like you would with the aforementioned 3D plotting functions. This can be done with imagesc
.
Typically you would want your axes to be the dependent variables. Could you elaborate more on this point?
If I understand you correctly you have calculated a function f(theta,phi)
and now you want to plot the surface containing all the points with the polar coordinated (r,theta,phi)
where r=f(theta,phi)
.
If this is what you want to do, the 2D version of such a plot is included in MATLAB under the name polar
. Unfortunately, as you pointed out, polar3
on MatlabCentral is not the generalization you are looking for.
I have been able to plot a sphere with the following code, using constant r=1
. You can give it a try with your function:
phi1=0:1/(3*pi):pi; %# this would be your 180 points
theta1=-pi:1/(3*pi):pi; % your 360 points
r=ones(numel(theta1),numel(phi1));
[phi,theta]=meshgrid(phi1,theta1);
x=r.*sin(theta).*cos(phi);
y=r.*sin(theta).*sin(phi);
z=r.*cos(theta);
tri=delaunay(x(:),y(:),z(:));
trisurf(tri,x,y,z);
From my tests it seems that delaunay
also includes a lot of triangles which go through the volume of my sphere, so it seems this is not optimal. So maybe you can have a look at fill3
and construct the triangles it draws itself: as a first approximation, you could have the points [x(n,m) x(n+1,m) x(n,m+1)]
combined into one triangle, and [x(n+1,m) x(n+1,m+1) x(n+1,m+1)]
into another...?
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