Documentation

# stream2

Compute 2-D streamline data

## Syntax

```XY = stream2(x,y,u,v,startx,starty) XY = stream2(u,v,startx,starty) XY = stream2(...,options) ```

## Description

`XY = stream2(x,y,u,v,startx,starty) ` computes streamlines from vector data `u` and `v`.

The arrays `x` and `y`, which define the coordinates for `u` and `v`, must be monotonic, but do not need to be uniformly spaced. `x` and `y` must have the same number of elements, as if produced by `meshgrid`.

`startx` and `starty` define the starting positions of the streamlines.

The returned value `XY` contains a cell array of vertex arrays.

`XY = stream2(u,v,startx,starty) ` assumes the arrays `x` and `y` are defined as `[x,y] = meshgrid(1:n,1:m)` where ```[m,n] = size(u)```.

`XY = stream2(...,options) ` specifies the options used when creating the streamlines. Define `options` as a one- or two-element vector containing the step size or the step size and the maximum number of vertices in a streamline:

```[stepsize] ```

or

```[stepsize, max_number_vertices] ```

If you do not specify a value, MATLAB® software uses the default:

• Step size = 0.1 (one tenth of a cell)

• Maximum number of vertices = 10000

Use the `streamline` command to plot the data returned by `stream2`.

## Examples

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Plot 2-D streamlines from data representing air currents over regions of North America.

```load wind [sx,sy] = meshgrid(80,20:10:50); streamline(stream2(x(:,:,5),y(:,:,5),u(:,:,5),v(:,:,5),sx,sy));``` 