matplotlib.quiver.Quiver¶

class matplotlib.quiver.Quiver(ax, *args, scale=None, headwidth=3, headlength=5, headaxislength=4.5, minshaft=1, minlength=1, units='width', scale_units=None, angles='uv', width=None, color='k', pivot='tail', **kw)[source]¶

Bases: matplotlib.collections.PolyCollection

Specialized PolyCollection for arrows.

The only API method is set_UVC(), which can be used to change the size, orientation, and color of the arrows; their locations are fixed when the class is instantiated. Possibly this method will be useful in animations.

Much of the work in this class is done in the draw() method so that as much information as possible is available about the plot. In subsequent draw() calls, recalculation is limited to things that might have changed, so there should be no performance penalty from putting the calculations in the draw() method.

Plot a 2D field of arrows.

Call signature:

quiver([X, Y], U, V, [C], **kw)

X, Y define the arrow locations, U, V define the arrow directions, and C optionally sets the color.

Arrow size

The default settings auto-scales the length of the arrows to a reasonable size. To change this behavior see the scale and scale_units parameters.

Arrow shape

The defaults give a slightly swept-back arrow; to make the head a triangle, make headaxislength the same as headlength. To make the arrow more pointed, reduce headwidth or increase headlength and headaxislength. To make the head smaller relative to the shaft, scale down all the head parameters. You will probably do best to leave minshaft alone.

Arrow outline

linewidths and edgecolors can be used to customize the arrow outlines.

Parameters:

X, Y1D or 2D array-like, optional

The x and y coordinates of the arrow locations.

If not given, they will be generated as a uniform integer meshgrid based on the dimensions of U and V.

If X and Y are 1D but U, V are 2D, X, Y are expanded to 2D using X, Y = np.meshgrid(X, Y). In this case len(X) and len(Y) must match the column and row dimensions of U and V.

U, V1D or 2D array-like

The x and y direction components of the arrow vectors.

They must have the same number of elements, matching the number of arrow locations. U and V may be masked. Only locations unmasked in U, V, and C will be drawn.

C1D or 2D array-like, optional

Numeric data that defines the arrow colors by colormapping via norm and cmap.

This does not support explicit colors. If you want to set colors directly, use color instead. The size of C must match the number of arrow locations.

units{'width', 'height', 'dots', 'inches', 'x', 'y' 'xy'}, default: 'width'

The arrow dimensions (except for length) are measured in multiples of this unit.

The following values are supported:

'width', 'height': The width or height of the axis.
'dots', 'inches': Pixels or inches based on the figure dpi.
'x', 'y', 'xy': X, Y or \(\sqrt{X^2 + Y^2}\) in data units.

The arrows scale differently depending on the units. For 'x' or 'y', the arrows get larger as one zooms in; for other units, the arrow size is independent of the zoom state. For 'width or 'height', the arrow size increases with the width and height of the axes, respectively, when the window is resized; for 'dots' or 'inches', resizing does not change the arrows.

angles{'uv', 'xy'} or array-like, default: 'uv'

Method for determining the angle of the arrows.

'uv': The arrow axis aspect ratio is 1 so that if U == V the orientation of the arrow on the plot is 45 degrees counter-clockwise from the horizontal axis (positive to the right).

Use this if the arrows symbolize a quantity that is not based on X, Y data coordinates.
'xy': Arrows point from (x, y) to (x+u, y+v). Use this for plotting a gradient field, for example.
Alternatively, arbitrary angles may be specified explicitly as an array of values in degrees, counter-clockwise from the horizontal axis.

In this case U, V is only used to determine the length of the arrows.

Note: inverting a data axis will correspondingly invert the arrows only with angles='xy'.

scalefloat, optional

Number of data units per arrow length unit, e.g., m/s per plot width; a smaller scale parameter makes the arrow longer. Default is None.

If None, a simple autoscaling algorithm is used, based on the average vector length and the number of vectors. The arrow length unit is given by the scale_units parameter.

scale_units{'width', 'height', 'dots', 'inches', 'x', 'y', 'xy'}, optional

If the scale kwarg is None, the arrow length unit. Default is None.

e.g. scale_units is 'inches', scale is 2.0, and (u, v) = (1, 0), then the vector will be 0.5 inches long.

If scale_units is 'width' or 'height', then the vector will be half the width/height of the axes.

If scale_units is 'x' then the vector will be 0.5 x-axis units. To plot vectors in the x-y plane, with u and v having the same units as x and y, use angles='xy', scale_units='xy', scale=1.

widthfloat, optional

Shaft width in arrow units; default depends on choice of units, above, and number of vectors; a typical starting value is about 0.005 times the width of the plot.

headwidthfloat, default: 3

Head width as multiple of shaft width.

headlengthfloat, default: 5

Head length as multiple of shaft width.

headaxislengthfloat, default: 4.5

Head length at shaft intersection.

minshaftfloat, default: 1

Length below which arrow scales, in units of head length. Do not set this to less than 1, or small arrows will look terrible!

minlengthfloat, default: 1

Minimum length as a multiple of shaft width; if an arrow length is less than this, plot a dot (hexagon) of this diameter instead.

pivot{'tail', 'mid', 'middle', 'tip'}, default: 'tail'

The part of the arrow that is anchored to the X, Y grid. The arrow rotates about this point.

'mid' is a synonym for 'middle'.

colorcolor or color sequence, optional

Explicit color(s) for the arrows. If C has been set, color has no effect.

This is a synonym for the PolyCollection facecolor parameter.

Other Parameters:

**kwargsPolyCollection properties, optional

All other keyword arguments are passed on to PolyCollection:

Property	Description
`agg_filter`	a filter function, which takes a (m, n, 3) float array and a dpi value, and returns a (m, n, 3) array
`alpha`	float or None
`animated`	bool
`antialiased` or aa or antialiaseds	bool or list of bools
`array`	ndarray
`capstyle`	{'butt', 'round', 'projecting'}
`clim`	(vmin: float, vmax: float)
`clip_box`	`Bbox`
`clip_on`	bool
`clip_path`	Patch or (Path, Transform) or None
`cmap`	`Colormap` or str or None
`color`	color or list of rgba tuples
`contains`	unknown
`edgecolor` or ec or edgecolors	color or list of colors or 'face'
`facecolor` or facecolors or fc	color or list of colors
`figure`	`Figure`
`gid`	str
`hatch`	{'/', '\', '\|', '-', '+', 'x', 'o', 'O', '.', '*'}
`in_layout`	bool
`joinstyle`	{'miter', 'round', 'bevel'}
`label`	object
`linestyle` or dashes or linestyles or ls	str or tuple or list thereof
`linewidth` or linewidths or lw	float or list of floats
`norm`	`Normalize` or None
`offset_position`	unknown
`offsets`	array-like (N, 2) or (2,)
`path_effects`	`AbstractPathEffect`
`picker`	None or bool or callable
`pickradius`	unknown
`rasterized`	bool or None
`sketch_params`	(scale: float, length: float, randomness: float)
`snap`	bool or None
`transform`	`Transform`
`url`	str
`urls`	list of str or None
`visible`	bool
`zorder`	float

See also

Axes.quiverkey: Add a key to a quiver plot.

__init__(self, ax, *args, scale=None, headwidth=3, headlength=5, headaxislength=4.5, minshaft=1, minlength=1, units='width', scale_units=None, angles='uv', width=None, color='k', pivot='tail', **kw)[source]¶

The constructor takes one required argument, an Axes instance, followed by the args and kwargs described by the following pyplot interface documentation:

Plot a 2D field of arrows.

Call signature:

quiver([X, Y], U, V, [C], **kw)

X, Y define the arrow locations, U, V define the arrow directions, and C optionally sets the color.

Arrow size

The default settings auto-scales the length of the arrows to a reasonable size. To change this behavior see the scale and scale_units parameters.

Arrow shape

The defaults give a slightly swept-back arrow; to make the head a triangle, make headaxislength the same as headlength. To make the arrow more pointed, reduce headwidth or increase headlength and headaxislength. To make the head smaller relative to the shaft, scale down all the head parameters. You will probably do best to leave minshaft alone.

Arrow outline

linewidths and edgecolors can be used to customize the arrow outlines.

Parameters:

X, Y1D or 2D array-like, optional

The x and y coordinates of the arrow locations.

If not given, they will be generated as a uniform integer meshgrid based on the dimensions of U and V.

If X and Y are 1D but U, V are 2D, X, Y are expanded to 2D using X, Y = np.meshgrid(X, Y). In this case len(X) and len(Y) must match the column and row dimensions of U and V.

U, V1D or 2D array-like

The x and y direction components of the arrow vectors.

They must have the same number of elements, matching the number of arrow locations. U and V may be masked. Only locations unmasked in U, V, and C will be drawn.

C1D or 2D array-like, optional

Numeric data that defines the arrow colors by colormapping via norm and cmap.

This does not support explicit colors. If you want to set colors directly, use color instead. The size of C must match the number of arrow locations.

units{'width', 'height', 'dots', 'inches', 'x', 'y' 'xy'}, default: 'width'

The arrow dimensions (except for length) are measured in multiples of this unit.

The following values are supported:

'width', 'height': The width or height of the axis.
'dots', 'inches': Pixels or inches based on the figure dpi.
'x', 'y', 'xy': X, Y or \(\sqrt{X^2 + Y^2}\) in data units.

The arrows scale differently depending on the units. For 'x' or 'y', the arrows get larger as one zooms in; for other units, the arrow size is independent of the zoom state. For 'width or 'height', the arrow size increases with the width and height of the axes, respectively, when the window is resized; for 'dots' or 'inches', resizing does not change the arrows.

angles{'uv', 'xy'} or array-like, default: 'uv'

Method for determining the angle of the arrows.

'uv': The arrow axis aspect ratio is 1 so that if U == V the orientation of the arrow on the plot is 45 degrees counter-clockwise from the horizontal axis (positive to the right).

Use this if the arrows symbolize a quantity that is not based on X, Y data coordinates.
'xy': Arrows point from (x, y) to (x+u, y+v). Use this for plotting a gradient field, for example.
Alternatively, arbitrary angles may be specified explicitly as an array of values in degrees, counter-clockwise from the horizontal axis.

In this case U, V is only used to determine the length of the arrows.

Note: inverting a data axis will correspondingly invert the arrows only with angles='xy'.

scalefloat, optional

Number of data units per arrow length unit, e.g., m/s per plot width; a smaller scale parameter makes the arrow longer. Default is None.

If None, a simple autoscaling algorithm is used, based on the average vector length and the number of vectors. The arrow length unit is given by the scale_units parameter.

scale_units{'width', 'height', 'dots', 'inches', 'x', 'y', 'xy'}, optional

If the scale kwarg is None, the arrow length unit. Default is None.

e.g. scale_units is 'inches', scale is 2.0, and (u, v) = (1, 0), then the vector will be 0.5 inches long.

If scale_units is 'width' or 'height', then the vector will be half the width/height of the axes.

If scale_units is 'x' then the vector will be 0.5 x-axis units. To plot vectors in the x-y plane, with u and v having the same units as x and y, use angles='xy', scale_units='xy', scale=1.

widthfloat, optional

Shaft width in arrow units; default depends on choice of units, above, and number of vectors; a typical starting value is about 0.005 times the width of the plot.

headwidthfloat, default: 3

Head width as multiple of shaft width.

headlengthfloat, default: 5

Head length as multiple of shaft width.

headaxislengthfloat, default: 4.5

Head length at shaft intersection.

minshaftfloat, default: 1

Length below which arrow scales, in units of head length. Do not set this to less than 1, or small arrows will look terrible!

minlengthfloat, default: 1

Minimum length as a multiple of shaft width; if an arrow length is less than this, plot a dot (hexagon) of this diameter instead.

pivot{'tail', 'mid', 'middle', 'tip'}, default: 'tail'

The part of the arrow that is anchored to the X, Y grid. The arrow rotates about this point.

'mid' is a synonym for 'middle'.

colorcolor or color sequence, optional

Explicit color(s) for the arrows. If C has been set, color has no effect.

This is a synonym for the PolyCollection facecolor parameter.

Other Parameters:

**kwargsPolyCollection properties, optional

All other keyword arguments are passed on to PolyCollection:

Property	Description
`agg_filter`	a filter function, which takes a (m, n, 3) float array and a dpi value, and returns a (m, n, 3) array
`alpha`	float or None
`animated`	bool
`antialiased` or aa or antialiaseds	bool or list of bools
`array`	ndarray
`capstyle`	{'butt', 'round', 'projecting'}
`clim`	(vmin: float, vmax: float)
`clip_box`	`Bbox`
`clip_on`	bool
`clip_path`	Patch or (Path, Transform) or None
`cmap`	`Colormap` or str or None
`color`	color or list of rgba tuples
`contains`	unknown
`edgecolor` or ec or edgecolors	color or list of colors or 'face'
`facecolor` or facecolors or fc	color or list of colors
`figure`	`Figure`
`gid`	str
`hatch`	{'/', '\', '\|', '-', '+', 'x', 'o', 'O', '.', '*'}
`in_layout`	bool
`joinstyle`	{'miter', 'round', 'bevel'}
`label`	object
`linestyle` or dashes or linestyles or ls	str or tuple or list thereof
`linewidth` or linewidths or lw	float or list of floats
`norm`	`Normalize` or None
`offset_position`	unknown
`offsets`	array-like (N, 2) or (2,)
`path_effects`	`AbstractPathEffect`
`picker`	None or bool or callable
`pickradius`	unknown
`rasterized`	bool or None
`sketch_params`	(scale: float, length: float, randomness: float)
`snap`	bool or None
`transform`	`Transform`
`url`	str
`urls`	list of str or None
`visible`	bool
`zorder`	float

See also

Axes.quiverkey: Add a key to a quiver plot.

__module__ = 'matplotlib.quiver'¶

ax(self)[source]¶

[Deprecated]

Notes

Deprecated since version 3.3:

draw(self, renderer)[source]¶

Draw the Artist (and its children) using the given renderer.

This has no effect if the artist is not visible (Artist.get_visible returns False).

Parameters:	renderer`RendererBase` subclass.

Notes

This method is overridden in the Artist subclasses.

get_datalim(self, transData)[source]¶

quiver_doc = "\nPlot a 2D field of arrows.\n\nCall signature::\n\n quiver([X, Y], U, V, [C], **kw)\n\n*X*, *Y* define the arrow locations, *U*, *V* define the arrow directions, and\n*C* optionally sets the color.\n\n**Arrow size**\n\nThe default settings auto-scales the length of the arrows to a reasonable size.\nTo change this behavior see the *scale* and *scale_units* parameters.\n\n**Arrow shape**\n\nThe defaults give a slightly swept-back arrow; to make the head a\ntriangle, make *headaxislength* the same as *headlength*. To make the\narrow more pointed, reduce *headwidth* or increase *headlength* and\n*headaxislength*. To make the head smaller relative to the shaft,\nscale down all the head parameters. You will probably do best to leave\nminshaft alone.\n\n**Arrow outline**\n\n*linewidths* and *edgecolors* can be used to customize the arrow\noutlines.\n\nParameters\n----------\nX, Y : 1D or 2D array-like, optional\n The x and y coordinates of the arrow locations.\n\n If not given, they will be generated as a uniform integer meshgrid based\n on the dimensions of *U* and *V*.\n\n If *X* and *Y* are 1D but *U*, *V* are 2D, *X*, *Y* are expanded to 2D\n using ``X, Y = np.meshgrid(X, Y)``. In this case ``len(X)`` and ``len(Y)``\n must match the column and row dimensions of *U* and *V*.\n\nU, V : 1D or 2D array-like\n The x and y direction components of the arrow vectors.\n\n They must have the same number of elements, matching the number of arrow\n locations. *U* and *V* may be masked. Only locations unmasked in\n *U*, *V*, and *C* will be drawn.\n\nC : 1D or 2D array-like, optional\n Numeric data that defines the arrow colors by colormapping via *norm* and\n *cmap*.\n\n This does not support explicit colors. If you want to set colors directly,\n use *color* instead. The size of *C* must match the number of arrow\n locations.\n\nunits : {'width', 'height', 'dots', 'inches', 'x', 'y' 'xy'}, default: 'width'\n The arrow dimensions (except for *length*) are measured in multiples of\n this unit.\n\n The following values are supported:\n\n - 'width', 'height': The width or height of the axis.\n - 'dots', 'inches': Pixels or inches based on the figure dpi.\n - 'x', 'y', 'xy': *X*, *Y* or :math:`\\sqrt{X^2 + Y^2}` in data units.\n\n The arrows scale differently depending on the units. For\n 'x' or 'y', the arrows get larger as one zooms in; for other\n units, the arrow size is independent of the zoom state. For\n 'width or 'height', the arrow size increases with the width and\n height of the axes, respectively, when the window is resized;\n for 'dots' or 'inches', resizing does not change the arrows.\n\nangles : {'uv', 'xy'} or array-like, default: 'uv'\n Method for determining the angle of the arrows.\n\n - 'uv': The arrow axis aspect ratio is 1 so that\n if *U* == *V* the orientation of the arrow on the plot is 45 degrees\n counter-clockwise from the horizontal axis (positive to the right).\n\n Use this if the arrows symbolize a quantity that is not based on\n *X*, *Y* data coordinates.\n\n - 'xy': Arrows point from (x, y) to (x+u, y+v).\n Use this for plotting a gradient field, for example.\n\n - Alternatively, arbitrary angles may be specified explicitly as an array\n of values in degrees, counter-clockwise from the horizontal axis.\n\n In this case *U*, *V* is only used to determine the length of the\n arrows.\n\n Note: inverting a data axis will correspondingly invert the\n arrows only with ``angles='xy'``.\n\nscale : float, optional\n Number of data units per arrow length unit, e.g., m/s per plot width; a\n smaller scale parameter makes the arrow longer. Default is *None*.\n\n If *None*, a simple autoscaling algorithm is used, based on the average\n vector length and the number of vectors. The arrow length unit is given by\n the *scale_units* parameter.\n\nscale_units : {'width', 'height', 'dots', 'inches', 'x', 'y', 'xy'}, optional\n If the *scale* kwarg is *None*, the arrow length unit. Default is *None*.\n\n e.g. *scale_units* is 'inches', *scale* is 2.0, and ``(u, v) = (1, 0)``,\n then the vector will be 0.5 inches long.\n\n If *scale_units* is 'width' or 'height', then the vector will be half the\n width/height of the axes.\n\n If *scale_units* is 'x' then the vector will be 0.5 x-axis\n units. To plot vectors in the x-y plane, with u and v having\n the same units as x and y, use\n ``angles='xy', scale_units='xy', scale=1``.\n\nwidth : float, optional\n Shaft width in arrow units; default depends on choice of units,\n above, and number of vectors; a typical starting value is about\n 0.005 times the width of the plot.\n\nheadwidth : float, default: 3\n Head width as multiple of shaft width.\n\nheadlength : float, default: 5\n Head length as multiple of shaft width.\n\nheadaxislength : float, default: 4.5\n Head length at shaft intersection.\n\nminshaft : float, default: 1\n Length below which arrow scales, in units of head length. Do not\n set this to less than 1, or small arrows will look terrible!\n\nminlength : float, default: 1\n Minimum length as a multiple of shaft width; if an arrow length\n is less than this, plot a dot (hexagon) of this diameter instead.\n\npivot : {'tail', 'mid', 'middle', 'tip'}, default: 'tail'\n The part of the arrow that is anchored to the *X*, *Y* grid. The arrow\n rotates about this point.\n\n 'mid' is a synonym for 'middle'.\n\ncolor : color or color sequence, optional\n Explicit color(s) for the arrows. If *C* has been set, *color* has no\n effect.\n\n This is a synonym for the `~.PolyCollection` *facecolor* parameter.\n\nOther Parameters\n----------------\n**kwargs : `~matplotlib.collections.PolyCollection` properties, optional\n All other keyword arguments are passed on to `.PolyCollection`:\n\n \n .. table::\n :class: property-table\n\n ================================================================================================= =====================================================================================================\n Property Description \n ================================================================================================= =====================================================================================================\n :meth:`agg_filter <matplotlib.artist.Artist.set_agg_filter>` a filter function, which takes a (m, n, 3) float array and a dpi value, and returns a (m, n, 3) array\n :meth:`alpha <matplotlib.artist.Artist.set_alpha>` float or None \n :meth:`animated <matplotlib.artist.Artist.set_animated>` bool \n :meth:`antialiased <matplotlib.collections.Collection.set_antialiased>` or aa or antialiaseds bool or list of bools \n :meth:`array <matplotlib.cm.ScalarMappable.set_array>` ndarray \n :meth:`capstyle <matplotlib.collections.Collection.set_capstyle>` {'butt', 'round', 'projecting'} \n :meth:`clim <matplotlib.cm.ScalarMappable.set_clim>` (vmin: float, vmax: float) \n :meth:`clip_box <matplotlib.artist.Artist.set_clip_box>` `.Bbox` \n :meth:`clip_on <matplotlib.artist.Artist.set_clip_on>` bool \n :meth:`clip_path <matplotlib.artist.Artist.set_clip_path>` Patch or (Path, Transform) or None \n :meth:`cmap <matplotlib.cm.ScalarMappable.set_cmap>` `.Colormap` or str or None \n :meth:`color <matplotlib.collections.Collection.set_color>` color or list of rgba tuples \n :meth:`contains <matplotlib.artist.Artist.set_contains>` unknown \n :meth:`edgecolor <matplotlib.collections.Collection.set_edgecolor>` or ec or edgecolors color or list of colors or 'face' \n :meth:`facecolor <matplotlib.collections.Collection.set_facecolor>` or facecolors or fc color or list of colors \n :meth:`figure <matplotlib.artist.Artist.set_figure>` `.Figure` \n :meth:`gid <matplotlib.artist.Artist.set_gid>` str \n :meth:`hatch <matplotlib.collections.Collection.set_hatch>` {'/', '\\\\', '|', '-', '+', 'x', 'o', 'O', '.', '*'} \n :meth:`in_layout <matplotlib.artist.Artist.set_in_layout>` bool \n :meth:`joinstyle <matplotlib.collections.Collection.set_joinstyle>` {'miter', 'round', 'bevel'} \n :meth:`label <matplotlib.artist.Artist.set_label>` object \n :meth:`linestyle <matplotlib.collections.Collection.set_linestyle>` or dashes or linestyles or ls str or tuple or list thereof \n :meth:`linewidth <matplotlib.collections.Collection.set_linewidth>` or linewidths or lw float or list of floats \n :meth:`norm <matplotlib.cm.ScalarMappable.set_norm>` `.Normalize` or None \n :meth:`offset_position <matplotlib.collections.Collection.set_offset_position>` unknown \n :meth:`offsets <matplotlib.collections.Collection.set_offsets>` array-like (N, 2) or (2,) \n :meth:`path_effects <matplotlib.artist.Artist.set_path_effects>` `.AbstractPathEffect` \n :meth:`picker <matplotlib.artist.Artist.set_picker>` None or bool or callable \n :meth:`pickradius <matplotlib.collections.Collection.set_pickradius>` unknown \n :meth:`rasterized <matplotlib.artist.Artist.set_rasterized>` bool or None \n :meth:`sketch_params <matplotlib.artist.Artist.set_sketch_params>` (scale: float, length: float, randomness: float) \n :meth:`snap <matplotlib.artist.Artist.set_snap>` bool or None \n :meth:`transform <matplotlib.artist.Artist.set_transform>` `.Transform` \n :meth:`url <matplotlib.artist.Artist.set_url>` str \n :meth:`urls <matplotlib.collections.Collection.set_urls>` list of str or None \n :meth:`visible <matplotlib.artist.Artist.set_visible>` bool \n :meth:`zorder <matplotlib.artist.Artist.set_zorder>` float \n ================================================================================================= =====================================================================================================\n\n\nSee Also\n--------\n.Axes.quiverkey : Add a key to a quiver plot.\n"¶

remove(self)[source]¶

Remove the artist from the figure if possible.

The effect will not be visible until the figure is redrawn, e.g., with FigureCanvasBase.draw_idle. Call relim to update the axes limits if desired.

Note: relim will not see collections even if the collection was added to the axes with autolim = True.

Note: there is no support for removing the artist's legend entry.