__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)
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.
Each arrow is internally represented by a filled polygon with a default edge linewidth of 0. As a result, an arrow is rather a filled area, not a line with a head, and .PolyCollection
properties like linewidth, linestyle, facecolor, etc. act accordingly.
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.
DATA_PARAMETER_PLACEHOLDER
All other keyword arguments are passed on to .PolyCollection
:
Properties: 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: array-like or scalar or None animated: bool antialiased or aa or antialiaseds: bool or list of bools array: array-like or None capstyle: .CapStyle
or {'butt', 'projecting', 'round'} 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 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: .JoinStyle
or {'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_transform: .Transform
offsets: (N, 2) or (2,) array-like path_effects: .AbstractPathEffect
paths: list of array-like picker: None or bool or float or callable pickradius: float rasterized: bool sizes: ndarray or None sketch_params: (scale: float, length: float, randomness: float) snap: bool or None transform: .Transform
url: str urls: list of str or None verts: list of array-like verts_and_codes: unknown visible: bool zorder: float
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.
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.
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.
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.
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'
.
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.
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
.
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.
Head width as multiple of shaft width.
Head length as multiple of shaft width.
Head length at shaft intersection.
Length below which arrow scales, in units of head length. Do not set this to less than 1, or small arrows will look terrible!
Minimum length as a multiple of shaft width; if an arrow length is less than this, plot a dot (hexagon) of this diameter instead.
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'.
Explicit color(s) for the arrows. If C has been set, color has no effect.
This is a synonym for the .PolyCollection
facecolor parameter.
The constructor takes one required argument, an Axes instance, followed by the args and kwargs described by the following pyplot interface documentation:
.Axes.quiverkey
Add a key to a quiver plot.
Hover to see nodes names; edges to Self not shown, Caped at 50 nodes.
Using a canvas is more power efficient and can get hundred of nodes ; but does not allow hyperlinks; , arrows or text (beyond on hover)
SVG is more flexible but power hungry; and does not scale well to 50 + nodes.
All aboves nodes referred to, (or are referred from) current nodes; Edges from Self to other have been omitted (or all nodes would be connected to the central node "self" which is not useful). Nodes are colored by the library they belong to, and scaled with the number of references pointing them