Make a 3D plot over a circle
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Hello everyone,
I am currently researching the characteristic of a fan. Therefore I am measuring the wind speed on 9 different points as can be seen in the attachment: 'Ventilator en meetpunten'.
I plotted the velocity at every point I measured it in a 2D plot as can be seen in the attachment: ''
The velocity values plotted on the y-axis are: 0, 0.854, 1.686, 6.7075, 8.52, 10.15, 10.4775, 9.825, 9.65, 0.
Is it possible to plot this 2D graph over a cirle (2*PI) in MatLab, so it becomes a 3D plot? If yes, I would like some help with it.
Thank you in advance.
With kind regards,
Bob Schreurs
采纳的回答
There are tons of options for doing this in MATLAB. Here are a few:
% First define some constants and your input data (as I understand it from
% the picture).
centerRadius = 150/2;
outerRadius = 730/2;
windSpeed = [0, 0.854, 1.686, 6.7075, 8.52, 10.15, 10.4775, 9.825, 9.65, 0];
theta = zeros(size(windSpeed));
r = linspace(centerRadius, outerRadius, numel(windSpeed));
The first option is to use the rectangle command to draw circles and scatter3 to draw dots at each reading. These circles will be drawn at Z = 0.
figure
x = r.*cos(theta);
y = r.*sin(theta);
scatter3(x, y, windSpeed, 'filled')
rectangle('Position',outerRadius*[-1 -1 2 2], 'Curvature', [1 1])
rectangle('Position',centerRadius*[-1 -1 2 2], 'Curvature', [1 1])
If you want to draw those "rectangles" at something other than Z = 0, then you can use an hgtransform.
figure
x = r.*cos(theta);
y = r.*sin(theta);
scatter3(x, y, windSpeed, 'filled')
t = hgtransform;
rectangle('Parent',t,'Position',outerRadius*[-1 -1 2 2], 'Curvature', [1 1])
rectangle('Parent',t,'Position',centerRadius*[-1 -1 2 2], 'Curvature', [1 1])
t.Matrix = makehgtform('translate', [0 0 5]);
More likely you want to draw some kind of 3D cylinder, and you can do that using a combination of cylinder and surface.
figure
x = r.*cos(theta);
y = r.*sin(theta);
scatter3(x, y, windSpeed, 'filled')
[x, y, z] = cylinder(outerRadius, 101);
surface(x,y,z*max(windSpeed),'FaceAlpha',0.1,'EdgeColor','none');
[x, y, z] = cylinder(centerRadius, 101);
surface(x,y,z*max(windSpeed),'FaceAlpha',0.1,'EdgeColor','none');
Do any of these pictures look like what you are trying to do?
5 个评论
Torsten
2022-1-26
I think the OP meant to rotate the measurement values around the z axis to create a 2d surface.
Bob Schreurs
2022-1-26
That makes much more sense. How does this look?
centerRadius = 150/2;
outerRadius = 730/2;
windSpeed = [0, 0.854, 1.686, 6.7075, 8.52, 10.15, 10.4775, 9.825, 9.65, 0];
theta = zeros(size(windSpeed));
r = linspace(centerRadius, outerRadius, numel(windSpeed));
[x, y, z] = cylinder(r, 100);
z = z.*windSpeed'; % Note the use of implicit scalar expansion
surf(x,y,z,'FaceAlpha', 0.4);
You can mess with how this looks by adjusting the CData, FaceColor, EdgeColor, FaceAlpha, EdgeAlpha, and AlphaData properties on the Surface object, or changing the view angle (using the view command).
Note I used implicit scalar expansion (see my comment in the code). When you use element-wise multiplication (.*) between a matrix and a vector, the vector is automatically replicated to match the size of the matrix. See this doc page for more details.
Bob Schreurs
2022-1-26
For example, I tweaked some more settings and overlayed two surfaces to get fewer edge lines but keep the smooth curve:
centerRadius = 150/2;
outerRadius = 730/2;
windSpeed = [0, 0.854, 1.686, 6.7075, 8.52, 10.15, 10.4775, 9.825, 9.65, 0];
theta = zeros(size(windSpeed));
r = linspace(centerRadius, outerRadius, numel(windSpeed));
[x, y, z] = cylinder(r, 361);
z = z.*windSpeed'; % Note the use of implicit scalar expansion
s = surf(x,y,z,'FaceAlpha', 0.4,'MeshStyle','row');
s.FaceColor = lines(1);
[x, y, z] = cylinder(r, 8);
z = z.*windSpeed';
surface(x,y,z,'FaceColor','none','MeshStyle','column')
view(-45, 70)
更多回答（1 个）
r=linspace(75,365,25);
phi=linspace(0,2*pi,36);
[R,PHI]=meshgrid(r,phi);
X=R.*cos(PHI);
Y=R.*sin(PHI);
Z=interp1(rm,velm,sqrt(X.^2+Y.^2));
surf(X,Y,Z)
where rm and velm are radius and velocity of your measurements.
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