matplotlib.pyplot.pcolor#

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

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

Call signature:

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

X andY can be used to specify the corners of the quadrilaterals.

The argumentsX,Y,C are positional-only.

Hint

pcolor() can be very slow for large arrays. In mostcases you should use the similar but much fasterpcolormesh instead. SeeDifferences between pcolor() and pcolormesh() for a discussion of thedifferences.

Parameters:

C2D array-like

The color-mapped values. Color-mapping is controlled bycmap,norm,vmin, andvmax.

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, andthe row index corresponds to y. For details, see theNotes section below.

Ifshading='flat' the dimensions ofX andY should be onegreater than those ofC, and the quadrilateral is colored dueto the value atC[i,j]. IfX,Y andC have equaldimensions, a warning will be raised and the last row and columnofC will be ignored.

Ifshading='nearest', the dimensions ofX andY should bethe same as those ofC (if not, a ValueError will be raised). ThecolorC[i,j] will be centered on(X[i,j],Y[i,j]).

IfX and/orY are 1-D arrays or column vectors they will beexpanded as needed into the appropriate 2D arrays, making arectangular grid.

shading{'flat', 'nearest', 'auto'}, default:rcParams["pcolor.shading"] (default:'auto')

The fill style for the quadrilateral. Possible values:

• 'flat': A solid color is used for each quad. The color of thequad (i, j), (i+1, j), (i, j+1), (i+1, j+1) is given byC[i,j]. The dimensions ofX andY should beone greater than those ofC; if they are the same asC,then a deprecation warning is raised, and the last rowand column ofC are dropped.

• 'nearest': Each grid point will have a color centered on it,extending halfway between the adjacent grid centers. Thedimensions ofX andY must be the same asC.

• 'auto': Choose 'flat' if dimensions ofX andY are onelarger thanC. Choose 'nearest' if dimensions are the same.

Seepcolormesh grids and shadingfor more description.

cmapstr orColormap, default:rcParams["image.cmap"] (default:'viridis')

The Colormap instance or registered colormap name used to map scalar datato colors.

normstr orNormalize, optional

The normalization method used to scale scalar data to the [0, 1] rangebefore mapping to colors usingcmap. By default, a linear scaling isused, mapping the lowest value to 0 and the highest to 1.

If given, this can be one of the following:

• An instance ofNormalize or one of its subclasses(seeColormap normalization).

• A scale name, i.e. one of "linear", "log", "symlog", "logit", etc. For alist of available scales, callmatplotlib.scale.get_scale_names().In that case, a suitableNormalize subclass is dynamically generatedand instantiated.

vmin, vmaxfloat, optional

When using scalar data and no explicitnorm,vmin andvmax definethe data range that the colormap covers. By default, the colormap coversthe complete value range of the supplied data. It is an error to usevmin/vmax when anorm instance is given (but using astrnormname together withvmin/vmax is acceptable).

colorizerColorizer or None, default: None

The Colorizer object used to map color to data. If None, a Colorizerobject is created from anorm andcmap.

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 currentlyrcParams["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 formedgecolor 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 bythis.

snapbool, default: False

Whether to snap the mesh to pixel boundaries.

Returns:

matplotlib.collections.PolyQuadMesh

Other Parameters:

antialiasedsbool, default: False

The defaultantialiaseds is False if the defaultedgecolors="none" is used. This eliminates artificial linesat patch boundaries, and works regardless of the value of alpha.Ifedgecolors is not "none", then the defaultantialiasedsis taken fromrcParams["patch.antialiased"] (default:True).Stroking the edges may be preferred ifalpha is 1, but willcause artifacts otherwise.

dataindexable object, optional

If given, all parameters also accept a strings, which isinterpreted asdata[s] ifs is a key indata.

**kwargs

Additionally, the following arguments are allowed. They are passedalong to thePolyQuadMesh 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 and two offsets from the bottom left corner of the image
alpha	array-like or float or None
animated	bool
antialiased oraa orantialiaseds	bool or list of bools
array	array-like or None
capstyle	CapStyle or {'butt', 'projecting', 'round'}
clim	(vmin: float, vmax: float)
clip_box	BboxBase or None
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 orec oredgecolors	color or list ofcolor or 'face'
facecolor orfacecolors orfc	color or list ofcolor
figure	Figure orSubFigure
gid	str
hatch	{'/', '\', '|', '-', '+', 'x', 'o', 'O', '.', '*'}
hatch_linewidth	unknown
hatchcolor	color or list ofcolor or 'edge'
in_layout	bool
joinstyle	JoinStyle or {'miter', 'round', 'bevel'}
label	object
linestyle ordashes orlinestyles orls	str or tuple or list thereof
linewidth orlinewidths orlw	float or list of floats
mouseover	bool
norm	Normalize or str or None
offset_transform ortransOffset	Transform
offsets	(N, 2) or (2,) array-like
path_effects	list ofAbstractPathEffect
paths	list of array-like
picker	None or bool or float or callable
pickradius	float
rasterized	bool
sizes	numpy.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

See also

pcolormesh

for an explanation of the differences between pcolor and pcolormesh.

imshow

IfX andY are each equidistant,imshow can be a faster alternative.

Notes

Note

This is thepyplot wrapper foraxes.Axes.pcolor.

Masked arrays

X,Y andC may be masked arrays. If eitherC[i,j], or oneof the vertices surroundingC[i,j] (X orY at[i,j],[i+1,j],[i,j+1],[i+1,j+1]) is masked, nothing isplotted.

Grid orientation

The grid orientation follows the standard matrix convention: An arrayC with shape (nrows, ncolumns) is plotted with the column number asX and the row number asY.

Examples usingmatplotlib.pyplot.pcolor#

pcolor images

pcolor images

Controlling view limits using margins and sticky_edges

Controlling view limits using margins and sticky_edges