matplotlib.pyplot.streamplot

matplotlib.pyplot.streamplot(x, y, u, v, density=1, linewidth=None, color=None, cmap=None, norm=None, arrowsize=1, arrowstyle='-|>', minlength=0.1, transform=None, zorder=None, start_points=None, maxlength=4.0, integration_direction='both', hold=None, data=None)

Draws streamlines of a vector flow.

x, y : 1d arrays

an evenly spaced grid.

u, v : 2d arrays

x and y-velocities. Number of rows should match length of y, and the number of columns should match x.

density : float or 2-tuple

Controls the closeness of streamlines. When density = 1, the domain is divided into a 30x30 grid—density linearly scales this grid. Each cell in the grid can have, at most, one traversing streamline. For different densities in each direction, use [density_x, density_y].

linewidth : numeric or 2d array

vary linewidth when given a 2d array with the same shape as velocities.

color : matplotlib color code, or 2d array

Streamline color. When given an array with the same shape as velocities, color values are converted to colors using cmap.

cmap : Colormap

Colormap used to plot streamlines and arrows. Only necessary when using an array input for color.

norm : Normalize

Normalize object used to scale luminance data to 0, 1. If None, stretch (min, max) to (0, 1). Only necessary when color is an array.

arrowsize : float

Factor scale arrow size.

arrowstyle : str

Arrow style specification. See FancyArrowPatch.

minlength : float

Minimum length of streamline in axes coordinates.

start_points: Nx2 array

Coordinates of starting points for the streamlines. In data coordinates, the same as the x and y arrays.

zorder : int

any number

maxlength : float

Maximum length of streamline in axes coordinates.

integration_direction : [‘forward’, ‘backward’, ‘both’]

Integrate the streamline in forward, backward or both directions.

Returns:

stream_container : StreamplotSet

Container object with attributes

• lines: matplotlib.collections.LineCollection of streamlines
• arrows: collection of matplotlib.patches.FancyArrowPatch objects representing arrows half-way along stream lines.

This container will probably change in the future to allow changes to the colormap, alpha, etc. for both lines and arrows, but these changes should be backward compatible.