pcolormesh([X, Y,] C, /, **kwargs)
X and Y can be used to specify the corners of the quadrilaterals.
The arguments X, Y, C are positional-only.
pcolormesh is similar to pcolor. It is much faster
and preferred in most cases. For a detailed discussion on the
differences see Differences between pcolor() and pcolormesh().
Parameters:
Carray-like
The mesh data. Supported array shapes are:
(M, N) or M*N: a mesh with scalar data. The values are mapped to
colors using normalization and a colormap. See parameters norm,
cmap, vmin, vmax.
(M, N, 3): an image with RGB values (0-1 float or 0-255 int).
(M, N, 4): an image with RGBA values (0-1 float or 0-255 int),
i.e. including transparency.
The first two dimensions (M, N) define the rows and columns of
the mesh data.
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' or 'gouraud', the dimensions of X
and Y should be the same as those of C (if not, a ValueError
will be raised).  For 'nearest' the color C[i, j] is
centered on (X[i, j], Y[i, j]).  For 'gouraud', a smooth
interpolation is carried out between the quadrilateral corners.
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.
cmapstr or Colormap, default: rcParams["image.cmap"] (default: 'viridis')
The Colormap instance or registered colormap name used to map scalar data
to colors.
normstr or Normalize, optional
The normalization method used to scale scalar data to the [0, 1] range
before mapping to colors using cmap. By default, a linear scaling is
used, mapping the lowest value to 0 and the highest to 1.
If given, this can be one of the following:
An instance of Normalize




    
 or one of its subclasses
(see Colormap normalization).
A scale name, i.e. one of "linear", "log", "symlog", "logit", etc.  For a
list of available scales, call matplotlib.scale.get_scale_names().
In that case, a suitable Normalize subclass is dynamically generated
and instantiated.
vmin, vmaxfloat, optional
When using scalar data and no explicit norm, vmin and vmax define
the data range that the colormap covers. By default, the colormap covers
the complete value range of the supplied data. It is an error to use
vmin/vmax when a norm instance is given (but using a str norm
name together with vmin/vmax is acceptable).
colorizerColorizer or None, default: None
The Colorizer object used to map color to data. If None, a Colorizer
object is created from a norm and cmap.
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, between 0 (transparent) and 1 (opaque).
shading{'flat', 'nearest', 'gouraud', 'auto'}, optional
The fill style for the quadrilateral; defaults to
rcParams["pcolor.shading"] (default: 'auto'). 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.
'gouraud': Each quad will be Gouraud shaded: The color of the
corners (i', j') are given by C[i', j']. The color values of
the area in between is interpolated from the corner values.
The dimensions of X and Y must be the same as C. When
Gouraud shading is used, edgecolors is ignored.
'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.
snapbool, default: False
Whether to snap the mesh to pixel boundaries.
rasterizedbool, optional
Rasterize the pcolormesh when drawing vector graphics.  This can
speed up rendering and produce smaller files for large data sets.
See also Rasterization for vector graphics.
Returns:
matplotlib.collections.QuadMesh

Other Parameters:
dataindexable object, optional
If given, all parameters also accept a string s, which is
interpreted as data[s] if s is a key in data.
**kwargs
Additionally, the following arguments are allowed. They are passed
along to the QuadMesh 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
antialiased or aa or antialiaseds
bool or list of bools
array
array-like
capstyle
CapStyle or {'butt', 'projecting', 'round'}
(vmin: float, vmax: float)
clip_box
BboxBase or None
clip_on
clip_path
Patch or (Path, Transform) or None
Colormap or str or None
color
color or list of RGBA tuples
edgecolor or ec or edgecolors
color or list of color or 'face'
facecolor or facecolors or fc
color or list of color
figure
Figure or SubFigure
hatch
{'/', '\', '|', '-', '+', 'x', 'o', 'O', '.', '*'}
hatch_linewidth
unknown
in_layout
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
mouseover
Normalize




    
 or str or None
offset_transform or transOffset
Transform
offsets
(N, 2) or (2,) array-like
path_effects
list of AbstractPathEffect
picker
None or bool or float or callable
pickradius
float
rasterized
sketch_params
(scale: float, length: float, randomness: float)
bool or None
transform
Transform
list of str or None
visible
zorder
float
See also
pcolor
An alternative implementation with slightly different features. For a detailed discussion on the differences see Differences between pcolor() and pcolormesh().
imshow
If X and Y are each equidistant, imshow can be a faster alternative.
Notes
This is the pyplot wrapper for axes.Axes.pcolormesh.
Masked arrays
C may be a masked array. If C[i, j] is masked, the corresponding
quadrilateral will be transparent. Masking of X and Y is not
supported. Use pcolor if you need this functionality.
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.
Differences between pcolor() and pcolormesh()
Both methods are used to create a pseudocolor plot of a 2D array
using quadrilaterals.
The main difference lies in the created object and internal data
handling:
While pcolor returns a PolyQuadMesh, pcolormesh
returns a QuadMesh. The latter is more specialized for the given
purpose and thus is faster. It should almost always be preferred.
There is also a slight difference in the handling of masked arrays.
Both pcolor and pcolormesh support masked arrays
for C. However, only pcolor supports masked arrays for X
and Y. The reason lies in the internal handling of the masked values.
pcolor leaves out the respective polygons from the
PolyQuadMesh. pcolormesh sets the facecolor of the masked
elements to transparent. You can see the difference when using
edgecolors. While all edges are drawn irrespective of masking in a
QuadMesh, the edge between two adjacent masked quadrilaterals in
pcolor is not drawn as the corresponding polygons do not
exist in the PolyQuadMesh. Because PolyQuadMesh draws each individual
polygon, it also supports applying hatches and linestyles to the collection.
Another difference is the support of Gouraud shading in
pcolormesh, which is not available with pcolor.
Examples using matplotlib.pyplot.pcolormesh#
pcolor images
  
pcolor images
pcolormesh grids and shading
  
pcolormesh grids and shading
pcolormesh
  
pcolormesh
QuadMesh Demo
  
QuadMesh Demo
Rasterization for vector graphics
  
Rasterization for vector graphics
Time Series Histogram
  
Time Series Histogram