MATLAB Function Reference |

Interpolate stream line vertices from flow speed

**Syntax**

interpstreamspeed(X,Y,Z,U,V,W,vertices) interpstreamspeed(U,V,W,vertices) interpstreamspeed(X,Y,Z,speed,vertices) interpstreamspeed(speed,vertices) interpstreamspeed(X,Y,U,V,vertices) interpstreamspeed(U,V,vertices) interpstreamspeed(X,Y,speed,vertices) interpstreamspeed(speed,vertices) interpstreamspeed(...,sf) vertsout = interpstreamspeed(...)

**Description**

interpolates stream line vertices based on the magnitude of the vector data ```
interpstreamspeed(X,Y,Z,U,V,W,vertices)
```

`U`

, `V`

, `W`

. The arrays `X`

, `Y`

, `Z`

define the coordinates for `U`

, `V`

, `W`

and must be monotonic and 3-D plaid (as if produced by `meshgrid`

).

```
interpstreamspeed(U,V,W,vertices)
```

assumes `X`

, `Y`

, and `Z`

are determined by the expression:

```
interpstreamspeed(X,Y,Z,speed,vertices)
```

uses the 3-D array `speed`

for the speed of the vector field.

```
interpstreamspeed(speed,vertices)
```

assumes `X`

, `Y`

, and `Z`

are determined by the expression:

```
interpstreamspeed(X,Y,U,V,vertices)
```

interpolates streamline vertices based on the magnitude of the vector data `U`

, `V`

. The arrays `X`

, `Y`

define the coordinates for `U`

, `V`

and must be monotonic and 2-D plaid (as if produced by `meshgrid`

)

```
interpstreamspeed(U,V,vertices)
```

assumes `X`

and `Y`

are determined by the expression:

```
interpstreamspeed(X,Y,speed,vertices)
```

uses the 2-D array `speed`

for the speed of the vector field.

```
interpstreamspeed(speed,vertices)
```

assumes `X`

and `Y`

are determined by the expression:

```
interpstreamspeed(...,sf)
```

uses `sf`

to scale the magnitude of the vector data and therefore controls the number of interpolated vertices. For example, if `sf`

is 3, then `interpstreamspeed`

creates only one third of the vertices.

```
vertsout = interpstreamspeed(...)
```

returns a cell array of vertex arrays.

**Examples**

This example draws stream lines using the vertices returned by `interpstreamspeed`

. Dot markers indicate the location of each vertex. This example enables you to visualize the relative speeds of the flow data. Stream lines having widely space vertices indicate faster flow; those with closely spaced vertices indicate slower flow.

load wind [sx sy sz] = meshgrid(80,20:1:55,5); verts = stream3(x,y,z,u,v,w,sx,sy,sz); iverts = interpstreamspeed(x,y,z,u,v,w,verts,.2); sl = streamline(iverts); set(sl,'Marker','.') axis tight; view(2); daspect([1 1 1])

This example plots stream lines whose vertex spacing indicates the value of the gradient along the stream line.

z = membrane(6,30); [u v] = gradient(z); [verts averts] = streamslice(u,v); iverts = interpstreamspeed(u,v,verts,15); sl = streamline(iverts); set(sl,'Marker','.') hold on; pcolor(z); shading interp axis tight; view(2); daspect([1 1 1])

**See Also**

`stream2`

, `stream3`

, `streamline`

, `streamslice`

, `streamparticles`

Volume Visualization for related functions

interpn | intersect |