Stream ribbons illustrate direction of flow, similar to stream
lines, but can also show rotation about the flow axis by twisting
the ribbon-shaped flow line. The
enables you to specify a twist angle (in radians) for each vertex
in the stream ribbons.
When used in conjunction with the
useful for displaying the curl angular velocity of a vector field.
The following example illustrates this technique.
Load and select a region of interest in the
the full data set first can help you select a region of interest.
load wind lims = [100.64 116.67 17.25 28.75 -0.02 6.86]; [x,y,z,u,v,w] = subvolume(x,y,z,u,v,w,lims);
Calculate the curl angular velocity and the wind speed.
cav = curl(x,y,z,u,v,w); wind_speed = sqrt(u.^2 + v.^2 + w.^2);
the stream line vertices with a step size of
the width of the ribbon by a factor of
2 to enhance
the visibility of the twisting (which indicates curl angular velocity).
streamribbon returns the handles
of the surface objects it creates, which are then used to set the
color to red (
FaceColor), the color of the surface
edges to light gray (
EdgeColor), and slightly increase
the brightness of the ambient light reflected when lighting is applied
[sx sy sz] = meshgrid(110,20:5:30,1:5); verts = stream3(x,y,z,u,v,w,sx,sy,sz,.5); h = streamribbon(verts,x,y,z,cav,wind_speed,2); set(h,'FaceColor','r',... 'EdgeColor',[.7 .7 .7],... 'AmbientStrength',.6)
axis(volumebounds(x,y,z,wind_speed)) grid on view(3) camlight right;