MATLAB Function Reference |

**Syntax**

quiver(U,V,U,V) quiver(X,Y) quiver(...,scale) quiver(...,

`LineSpec`

) quiver(...,`LineSpec`

'filled') h = quiver(...)*,*

**Description**

A quiver plot displays velocity vectors as arrows with components (`U`

,`V`

) at the points (`X`

,`Y`

).

For example, the first vector is defined by componets `U(1)`

,`V(1)`

and is displayed at the point `X(1)`

,`Y(1)`

.

```
quiver(X,Y,U,V)
```

plots vectors as arrows at the coordinates specifide in each corresponding pair of elements in `X`

and `Y`

. The matirces `X`

, `Y`

, `U`

, and `V`

must all be the same size and contain corresponding position and velocity components.

**Expanding X and Y Coordinates**

MATLAB expandes `X`

and `Y`

, if they are not matrices. This expansion is equivalent to calling `meshgrid`

to generate matrices from vectors:

[X,Y] =

`meshgrid`

(X,Y) quiver(X,Y,U,V)

In this case, the following must be true:

`length(X)`

`=`

`n`

and `length(Y)`

`=`

`m`

, where `[m,n]`

`=`

`size(U)`

`=`

`size(V)`

The vector `X`

corresponds to the columns of `U`

and `V`

, and vector `Y`

corresponds to the rows of `U`

and `V`

.

```
quiver(U,V)
```

draws vectors specified by `U`

and `V`

at equally spaced points in the x-y plane.

```
quiver(...,scale)
```

automatically scales the arrows to fit within the grid and then stretches them by the factor `scale`

. `scale`

`=`

`2`

doubles their relative length and `scale`

`=`

`0.5`

halves the length. Use `scale = 0`

to plot the velocity vectors without the automatic scaling.

`quiver(...,`

specifies line style, marker symbol, and color using any valid `LineSpec`

)
`LineSpec`

. `quiver`

draws the markers at the origin of the vectors.

`quiver(...,`

fills markers specified by `LineSpec`

'filled')
*,*`LineSpec`

.

```
h = quiver(...)
```

returns a vector of line handles.

**Examples**

Plot the gradient field of the function.

`[X,Y]`

`=`

`meshgrid`

`(-2:.2:2);`

`Z`

`=`

`X.`

*`exp(-X.^2 - Y.^2);`

[DX,DY] =`gradient`

(Z,.2,.2);`contour`

(X,Y,Z)`hold`

on quiver(X,Y,DX,DY) colormap hsv`grid`

off hold off

**See Also**

`contour`

, `LineSpec`

, `plot`

, `quiver3`

Direction and Velocity Plots for related functions

Two-Dimensional Quiver Plots for more examples

quit | quiver3 |