matplotlib.axes.Axes.pcolor

Axes.pcolor(*args, shading=None, alpha=None, norm=None, cmap=None, vmin=None, vmax=None, data=None, **kwargs)[source]

Create a pseudocolor plot with a non-regular rectangular grid.

Call signature:

pcolor([X, Y,] C, **kwargs)

X and Y can be used to specify the corners of the quadrilaterals.

Hint

pcolor() can be very slow for large arrays. In most cases you should use the similar but much faster pcolormesh instead. See Differences between pcolor() and pcolormesh() for a discussion of the differences.

Parameters:	C2D array-like The color-mapped values. X, Yarray-like, optional The coordinates of the corners of quadrilaterals of a pcolormesh: (X[i+1, j], Y[i+1, j]) (X[i+1, j+1], Y[i+1, j+1]) +-----+ | | +-----+ (X[i, j], Y[i, j]) (X[i, j+1], Y[i, j+1]) Note that the column index corresponds to the x-coordinate, and the row index corresponds to y. For details, see the Notes section below. If shading='flat' the dimensions of X and Y should be one greater than those of C, and the quadrilateral is colored due to the value at C[i, j]. If X, Y and C have equal dimensions, a warning will be raised and the last row and column of C will be ignored. If shading='nearest', the dimensions of X and Y should be the same as those of C (if not, a ValueError will be raised). The color C[i, j] will be centered on (X[i, j], Y[i, j]). If X and/or Y are 1-D arrays or column vectors they will be expanded as needed into the appropriate 2D arrays, making a rectangular grid. shading{'flat', 'nearest', 'auto'}, optional The fill style for the quadrilateral; defaults to 'flat' or rcParams["pcolor.shading"] (default: 'flat'). Possible values: 'flat': A solid color is used for each quad. The color of the quad (i, j), (i+1, j), (i, j+1), (i+1, j+1) is given by C[i, j]. The dimensions of X and Y should be one greater than those of C; if they are the same as C, then a deprecation warning is raised, and the last row and column of C are dropped. 'nearest': Each grid point will have a color centered on it, extending halfway between the adjacent grid centers. The dimensions of X and Y must be the same as C. 'auto': Choose 'flat' if dimensions of X and Y are one larger than C. Choose 'nearest' if dimensions are the same. See pcolormesh grids and shading for more description. cmapstr or Colormap, default: rcParams["image.cmap"] (default: 'viridis') A Colormap instance or registered colormap name. The colormap maps the C values to colors. normNormalize, optional The Normalize instance scales the data values to the canonical colormap range [0, 1] for mapping to colors. By default, the data range is mapped to the colorbar range using linear scaling. vmin, vmaxfloat, default: None The colorbar range. If None, suitable min/max values are automatically chosen by the Normalize instance (defaults to the respective min/max values of C in case of the default linear scaling). It is deprecated to use vmin/vmax when norm is given. edgecolors{'none', None, 'face', color, color sequence}, optional The color of the edges. Defaults to 'none'. Possible values: 'none' or '': No edge. None: rcParams["patch.edgecolor"] (default: 'black') will be used. Note that currently rcParams["patch.force_edgecolor"] (default: False) has to be True for this to work. 'face': Use the adjacent face color. A color or sequence of colors will set the edge color. The singular form edgecolor works as an alias. alphafloat, default: None The alpha blending value of the face color, between 0 (transparent) and 1 (opaque). Note: The edgecolor is currently not affected by this. snapbool, default: False Whether to snap the mesh to pixel boundaries.
Returns:	matplotlib.collections.Collection
Other Parameters:	antialiasedsbool, default: False The default antialiaseds is False if the default edgecolors="none" is used. This eliminates artificial lines at patch boundaries, and works regardless of the value of alpha. If edgecolors is not "none", then the default antialiaseds is taken from rcParams["patch.antialiased"] (default: True). Stroking the edges may be preferred if alpha is 1, but will cause artifacts otherwise. **kwargs Additionally, the following arguments are allowed. They are passed along to the PolyCollection constructor: 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 array-like or scalar or None animated bool antialiased or aa or antialiaseds bool or list of bools array ndarray 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 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 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_position unknown offsets (N, 2) or (2,) array-like path_effects AbstractPathEffect picker None or bool or float or callable pickradius float rasterized bool 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

pcolormesh

for an explanation of the differences between pcolor and pcolormesh.

imshow

If X and Y are each equidistant, imshow can be a faster alternative.

Notes

Masked arrays

X, Y and C may be masked arrays. If either C[i, j], or one of the vertices surrounding C[i, j] (X or Y at [i, j], [i+1, j], [i, j+1], [i+1, j+1]) is masked, nothing is plotted.

Grid orientation

The grid orientation follows the standard matrix convention: An array C with shape (nrows, ncolumns) is plotted with the column number as X and the row number as Y.

Note

In addition to the above described arguments, this function can take a data keyword argument. If such a data argument is given, every other argument can also be string s, which is interpreted as data[s] (unless this raises an exception).

Objects passed as data must support item access (data[s]) and membership test (s in data).

Examples using matplotlib.axes.Axes.pcolor

Pcolor Demo

Controlling view limits using margins and sticky_edges