Create 3-D Quiver Plot
Load sample data that represents air currents over North America. For this example, select a subset of the data.
load wind X = x(5:10,20:25,6:10); Y = y(5:10,20:25,6:10); Z = z(5:10,20:25,6:10); U = u(5:10,20:25,6:10); V = v(5:10,20:25,6:10); W = w(5:10,20:25,6:10);
Create a 3-D quiver plot of the subset you selected. The vectors X, Y, and Z represent the location of the base of each arrow, and U, V, and W represent the directional components of each arrow. By default, the quiver3 function shortens the arrows so they do not overlap. Call axis equal to use equal data unit lengths along each axis. This makes the arrows point in the correct direction.
quiver3(X,Y,Z,U,V,W) axis equal fig2plotly()
plot00create3dquiver_plot
Disable Automatic Scaling
By default, the quiver3 function shortens arrows so they do not overlap. To disable automatic scaling so that arrow lengths are determined entirely by U, V, and W, set the scale argument to 0.
For example, first return the x-, y-, and z-coordinates of a unit sphere with 10-by-10 faces. Calculate the directional components of its surface normals using the surfnorm function. Then, create a 3-D quiver plot with no automatic scaling.
[X,Y,Z] = sphere(10); [U,V,W] = surfnorm(X,Y,Z); quiver3(X,Y,Z,U,V,W,0) axis equal fig2plotly()
plot10disableautomatic_scaling
For comparison, create the plot with automatic scaling. Note that the arrows are shorter and do not overlap.
figure quiver3(X,Y,Z,U,V,W) axis equal fig2plotly()
plot11disableautomatic_scaling
Plot Vectors Normal to Surface
Plot vectors that are normal to the surface defined by the function z=xe-x2-y2. Use the quiver3 function to plot the vectors and the surf function to plot the surface.
First, create a grid of x- and y-values that are equally spaced. Use them to calculate z. Then, find the normal vectors.
[X,Y] = meshgrid(-2:0.25:2,-1:0.2:1); Z = X.*exp(-X.^2 - Y.^2); [U,V,W] = surfnorm(X,Y,Z); fig2plotly()
Display the vectors as a 3-D quiver plot. Then, display the surface in the same axes. Adjust the display so that the vectors appear normal to the surface by calling axis equal.
quiver3(X,Y,Z,U,V,W) hold on surf(X,Y,Z) axis equal fig2plotly()
plot21plotvectorsnormalto_surface
Specify Arrow Color
Create a 3-D quiver plot and specify a color for the arrows.
For example, first return the x-, y-, and z- coordinates of a surface. Calculate the directional components of its surface normals using the surfnorm function.
[X,Y] = meshgrid(-pi/2:pi/8:pi/2,-pi/2:pi/8:pi/2); Z = sin(X) + cos(Y); [U,V,W] = surfnorm(Z);
Then, create a 3-D quiver plot with red arrows.
quiver3(X,Y,Z,U,V,W,'r') axis equal fig2plotly()
plot30specifyarrow_color
Specify Axes for 3-D Quiver Plot
Starting in R2019b, you can display a tiling of plots using the tiledlayout and nexttile functions. Call the tiledlayout function to create a 1-by-2 tiled chart layout. Call the nexttile function to create an axes object and return the object as ax1. Create the left plot by passing ax1 to the quiver3 function. Add a title to the plot by passing the axes to the title function. Repeat the process to create the right plot.
[X,Y] = meshgrid(-2:0.25:0,-2:0.25:0); Z1 = -0.5*(X.^2 + Y.^2); [U1,V1,W1] = surfnorm(Z1); Z2 = -X.*Y; [U2,V2,W2] = surfnorm(Z2); tiledlayout(1,2) % Left plot ax1 = nexttile; quiver3(ax1,X,Y,Z1,U1,V1,W1) axis equal title(ax1,'Left Plot') % Right plot ax2 = nexttile; quiver3(ax2,X,Y,Z2,U2,V2,W2) axis equal title(ax2,'Right Plot') fig2plotly()
plot40specifyaxesfor3dquiver_plot
Modify 3-D Quiver Plot After Creation
Create a 3-D quiver plot and return the quiver object. Then, remove the arrowheads and add dot markers at the base of each arrow.
[X,Y] = meshgrid(-3:0.5:3,-3:0.5:3); Z = 0.2*(Y.^2 - X.^2); [U,V,W] = surfnorm(Z); q = quiver3(X,Y,Z,U,V,W); axis equal q.ShowArrowHead = 'off'; q.Marker = '.'; fig2plotly()
plot50modify3dquiverplotafter_creation
Use Stream Ribbons to Indicate Flow
Use stream ribbons to indicate the flow in a data set.
load wind [sx,sy,sz] = meshgrid(80,20:10:50,0:5:15); streamribbon(x,y,z,u,v,w,sx,sy,sz); axis tight shading interp view(3); camlight lighting gouraud fig2plotly()
plot00usestreamribbonstoindicateflow
Indicate Flow Using Precalculated Data
Use precalculated vertex data, curl average velocity, and speed to indicate flow.
load wind [sx,sy,sz] = meshgrid(80,20:10:50,0:5:15); verts = stream3(x,y,z,u,v,w,sx,sy,sz); cav = curl(x,y,z,u,v,w); spd = sqrt(u.^2 + v.^2 + w.^2).*.1; streamribbon(verts,x,y,z,cav,spd); axis tight shading interp view(3); camlight; lighting gouraud fig2plotly()
plot10indicateflowusingprecalculated_data
Using precalculated data enables you to use values other than those calculated from the single data source. In this case, the speed is reduced by a factor of 10 compared to the previous example.
Stream Ribbon With Twist Angle
Specify a twist angle for the stream ribbon
t = 0:.15:15;
verts = {[cos(t)' sin(t)' (t/3)']};
twistangle = {cos(t)'};
streamribbon(verts,twistangle);
axis tight
shading interp
view(3)
camlight
lighting gouraud
fig2plotly()
plot20streamribbonwithtwist_angle
Combination of Cone and Stream Ribbon Plots
Create 3-D arrays and a cone plot.
xmin = -7; xmax = 7; ymin = -7; ymax = 7; zmin = -7; zmax = 7; x = linspace(xmin,xmax,30); y = linspace(ymin,ymax,20); z = linspace(zmin,zmax,20); [x,y,z] = meshgrid(x,y,z); u = y; v = -x; w = 0*x+1; [cx,cy,cz] = meshgrid(linspace(xmin,xmax,30),... linspace(ymin,ymax,30),[-3 4]); h = coneplot(x,y,z,u,v,w,cx,cy,cz,'quiver'); set(h,'Color','k'); fig2plotly()
plot30combinationofconeandstreamribbon_plots
Plot two sets of stream ribbons. Then define the view and lighting.
[sx,sy,sz] = meshgrid([-1 0 1],[-1 0 1],-6); streamribbon(x,y,z,u,v,w,sx,sy,sz); [sx,sy,sz] = meshgrid([1:6],[0],-6); streamribbon(x,y,z,u,v,w,sx,sy,sz); shading interp view(-30,10) axis off tight camproj perspective camva(66) camlookat camdolly(0,0,.5,'fixtarget') camlight fig2plotly()
plot31combinationofconeandstreamribbon_plots
Plot Streamlines in Slice Plane
Load the wind data set, which loads the three-dimensional arrays u, v, w, x, y, and z. Draw streamlines along the slice plane where z = 5.
load wind streamslice(x,y,z,u,v,w,[],[],5) axis tight fig2plotly()
plot00plotstreamlinesinslice_plane