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streamline

Plot streamlines from 2-D or 3-D vector data

  • Three-dimensional space with plotted streamlines

Description

example

streamline(X,Y,Z,U,V,W,startX,startY,startZ) returns plotted streamlines for 3-D vector data. The inputs x, y, and z are vector data coordinates, U, V, and Z are vector data, and startX, startY, and startZ are the starting positions of the streamlines.

streamline(U,V,W,startX,startY,startZ) uses the default coordinate data for U, V, and W. The (X,Y,Z) location for each element in U, V, and W is based on the column, row, and page index, respectively.

example

streamline(X,Y,U,V,startX,startY) returns plotted streamlines for 2-D vector data. The inputs x and y are vector data coordinates, U and V are vector data, and startX and startY are the starting positions of the streamlines.

streamline(U,V,startX,startY) uses the default coordinate data for  U and V. The (x,y) location for each element in U and V is based on the column and row index, respectively.

example

streamline(verts) plots streamlines from vertices, specified as a cell array of vertex arrays (as returned by stream2, stream3, or streamslice).

streamline(___,options) plots streamlines using the specified options, defined as a one- or two-element vector with the form step or [step maxvert], where step is the step size in data units for interpolating the vector data and maxvert is the maximum number of vertices in a streamline. Use this argument with any of the input argument combinations from the previous syntaxes.

streamline(ax,___) plots streamlines into the specified axes, instead of into the current axes object (gca).

example

lineobj = streamline(___) returns a vector of one or more Line objects. Use lineobj to modify properties of the streamlines after creating them. For a list of properties, see Line Properties.

Examples

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Load the wind data set which contains measurements of air current over regions of North America.

  • 3-D arrays x, y, and z represent the locations of air current measurements.

  • 3-D arrays u, v, and w represent the velocity of the air current in 3-D vector fields.

Define the starting position of 16 hypothetical particles. In this case, the particles all start at x = 80 and have starting y positions ranging from 20 to 50 and starting z positions ranging from 0 to 15.

load wind
[startX,startY,startZ] = meshgrid(80,20:10:50,0:5:15);

Compute the 3-D streamline vertex data for a hypothetical particle placed into the air current at the collection of starting positions in startX, startY, and startZ.

verts = stream3(x,y,z,u,v,w,startX,startY,startZ);

Visualize the 3-D volume of vector fields with streamline.

streamline(verts)
view(3)

Figure contains an axes object. The axes object contains 16 objects of type line.

Load the wind data set, which contains measurements of air current over regions of North America.

  • 3-D arrays x and y represent the locations of air current measurements.

  • 3-D arrays u and v represent the velocity of the air current in 3-D vector fields.

Use the fifth page of the arrays. Define the starting position of four hypothetical particles. In this case, the four starting locations are (80, 20), (80, 30), (80, 40), and (80, 50).

load wind
x5 = x(:,:,5);
y5 = y(:,:,5);
u5 = u(:,:,5);
v5 = v(:,:,5);
[startX,startY] = meshgrid(80,20:10:50);

Compute the 2-D streamline vertex data for a hypothetical particle placed into the air current with stream2.

verts = stream2(x5,y5,u5,v5,startX,startY);

Visualize the 2-D matrix of vector fields with streamline.

streamline(verts)

Figure contains an axes object. The axes object contains 4 objects of type line.

Load the wind dataset and compute the vertices of streamlines that start at evenly spaced points on the plane x = 80. Then, plot the streamlines from the vertex data.

load wind
[startX,startY,startZ] = meshgrid(80,20:10:50,0:5:15);
verts = stream3(x,y,z,u,v,w,startX,startY,startZ);
streamline(verts)
axis tight
view(3);

Figure contains an axes object. The axes object contains 16 objects of type line.

Plot streamlines and store the returned Line objects in l.

[x,y] = meshgrid(-10:10);
u = 2.*x.*y;
v = y.^2 - x.^2;
l = streamslice(x,y,u,v);
axis tight

Figure contains an axes object. The axes object contains 112 objects of type line.

Set the line width of the streamlines to 2. Set their color to red. Use the set function to change the properties of all the streamlines at the same time.

set(l,'LineWidth',2)
set(l,'Color','r');

Figure contains an axes object. The axes object contains 112 objects of type line.

Input Arguments

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x-axis coordinates of vector data, specified as a 2-D or 3-D array. It must be monotonic, but does not need to be uniformly spaced. X must be the same size as Y, Z, U, V, and W.

You can use the meshgrid function to create X.

y-axis coordinates of vector data, specified as a 2-D or 3-D array. It must be monotonic, but does not need to be uniformly spaced. Y must be the same size as X, Z, U, V, and W.

You can use the meshgrid function to create Y.

z-axis coordinates of vector data, specified as a 3-D array. It must be monotonic, but does not need to be uniformly spaced. Z must be the same size as X, Y, U, V, and W.

You can use the meshgrid function to create Y.

x-components of vector data, specified as a 2-D or 3-D array. U must be the same size as X, Y, Z, V, and W.

y-components of vector data, specified as a 2-D or 3-D array. V must be the same size as X, Y, Z, U, and W.

z-components of vector data, specified as a 3-D array. W must be the same size as X, Y, Z, U, and V.

x-axis streamline starting positions, specified as a vector or matrix. startX must be a scalar or be the same size as startY and startZ.

y-axis streamline starting positions, specified as a vector or matrix. startY must be a scalar or be the same size as startX and startZ.

z-axis streamline starting positions, specified as a vector or matrix. startZ must be a scalar or be the same size as startX and startY.

Streamline vertices, specified as a cell array (as returned by stream2, stream3, or streamslice). Each element of the cell array is a matrix of vertices for one line.

Streamline options, specified as a one- or two-element vector with one of the following forms:

  • step

  • [step,maxvert]

step is the step size used to adjust the streamline resolution and determine the vertex locations for which streamline velocity is interpolated. maxvert is the maximum number of vertices calculated for a streamline before computation is complete.

The default step-size is 0.1, and the default maximum number of vertices is 10,000.

Target axes, specified as an Axes object. If you do not specify the axes, then the streamline function uses the current axes.

Extended Capabilities

Version History

Introduced before R2006a