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matplotlib colorbar

matplotlib.colorbar

Colorbar toolkit with two classes and a function:

ColorbarBase
the base class with full colorbar drawing functionality. It can be used as-is to make a colorbar for a given colormap; a mappable object (e.g., image) is not needed.
Colorbar
the derived class for use with images or contour plots.
make_axes()
a function for resizing an axes and adding a second axes suitable for a colorbar

The colorbar() method uses make_axes() and Colorbar; the colorbar() function is a thin wrapper over colorbar().

class matplotlib.colorbar.Colorbar(ax, mappable, **kw)

Bases: matplotlib.colorbar.ColorbarBase

add_lines(CS)
Add the lines from a non-filled ContourSet to the colorbar.
update_bruteforce(mappable)
Manually change any contour line colors. This is called when the image or contour plot to which this colorbar belongs is changed.
class matplotlib.colorbar.ColorbarBase(ax, cmap=None, norm=None, alpha=1.0, values=None, boundaries=None, orientation='vertical', extend='neither', spacing='uniform', ticks=None, format=None, drawedges=False, filled=True)

Bases: matplotlib.cm.ScalarMappable

Draw a colorbar in an existing axes.

This is a base class for the Colorbar class, which is the basis for the colorbar() method and pylab function.

It is also useful by itself for showing a colormap. If the cmap kwarg is given but boundaries and values are left as None, then the colormap will be displayed on a 0-1 scale. To show the under- and over-value colors, specify the norm as:

colors.Normalize(clip=False)

To show the colors versus index instead of on the 0-1 scale, use:

norm=colors.NoNorm.

Useful attributes:

ax
the Axes instance in which the colorbar is drawn
lines
a LineCollection if lines were drawn, otherwise None
dividers
a LineCollection if drawedges is True, otherwise None

Useful public methods are set_label() and add_lines().

add_lines(levels, colors, linewidths)
Draw lines on the colorbar.
draw_all()
Calculate any free parameters based on the current cmap and norm, and do all the drawing.
set_alpha(alpha)
set_label(label, **kw)
Label the long axis of the colorbar
matplotlib.colorbar.make_axes(parent, **kw)

Resize and reposition a parent axes, and return a child axes suitable for a colorbar:

cax, kw = make_axes(parent, **kw)

Keyword arguments may include the following (with defaults):

orientation
‘vertical’ or ‘horizontal’
Property Description
fraction 0.15; fraction of original axes to use for colorbar
pad 0.05 if vertical, 0.15 if horizontal; fraction of original axes between colorbar and new image axes
shrink 1.0; fraction by which to shrink the colorbar
aspect 20; ratio of long to short dimensions

All but the first of these are stripped from the input kw set.

Returns (cax, kw), the child axes and the reduced kw dictionary.