00001 """
These are classes to support contour plotting and
labelling for the axes class
"""
from __future__ import division
import warnings
import matplotlib as mpl
import numpy as np
from numpy import ma
import matplotlib._cntr as _cntr
import matplotlib.path as path
import matplotlib.ticker as ticker
import matplotlib.cm as cm
import matplotlib.colors as colors
import matplotlib.collections as collections
import matplotlib.font_manager as font_manager
import matplotlib.text as text
import matplotlib.cbook as cbook
00028 class ContourLabeler:
'''Mixin to provide labelling capability to ContourSet'''
00031 def clabel(self, *args, **kwargs):
"""
call signature::
clabel(cs, **kwargs)
adds labels to line contours in *cs*, where *cs* is a
:class:`~matplotlib.contour.ContourSet` object returned by
contour.
::
clabel(cs, v, **kwargs)
only labels contours listed in *v*.
Optional keyword arguments:
*fontsize*:
See http://matplotlib.sf.net/fonts.html
.. TODO: Update this link to new fonts document
*colors*:
- if *None*, the color of each label matches the color of
the corresponding contour
- if one string color, e.g. *colors* = 'r' or *colors* =
'red', all labels will be plotted in this color
- if a tuple of matplotlib color args (string, float, rgb, etc),
different labels will be plotted in different colors in the order
specified
*inline*:
controls whether the underlying contour is removed or
not. Default is *True*.
*fmt*:
a format string for the label. Default is '%1.3f'
"""
fontsize = kwargs.get('fontsize', None)
inline = kwargs.get('inline', 1)
self.fmt = kwargs.get('fmt', '%1.3f')
_colors = kwargs.get('colors', None)
if len(args) == 0:
levels = self.levels
indices = range(len(self.levels))
elif len(args) == 1:
levlabs = list(args[0])
indices, levels = [], []
for i, lev in enumerate(self.levels):
if lev in levlabs:
indices.append(i)
levels.append(lev)
if len(levels) < len(levlabs):
msg = "Specified levels " + str(levlabs)
msg += "\n don't match available levels "
msg += str(self.levels)
raise ValueError(msg)
else:
raise TypeError("Illegal arguments to clabel, see help(clabel)")
self.label_levels = levels
self.label_indices = indices
self.fp = font_manager.FontProperties()
if fontsize == None:
font_size = int(self.fp.get_size_in_points())
else:
if type(fontsize) not in [int, float, str]:
raise TypeError("Font size must be an integer number.")
# Can't it be floating point, as indicated in line above?
else:
if type(fontsize) == str:
font_size = int(self.fp.get_size_in_points())
else:
self.fp.set_size(fontsize)
font_size = fontsize
self.fslist = [font_size] * len(levels)
if _colors == None:
self.label_mappable = self
self.label_cvalues = np.take(self.cvalues, self.label_indices)
else:
cmap = colors.ListedColormap(_colors, N=len(self.label_levels))
self.label_cvalues = range(len(self.label_levels))
self.label_mappable = cm.ScalarMappable(cmap = cmap,
norm = colors.NoNorm())
#self.cl = [] # Initialized in ContourSet.__init__
#self.cl_cvalues = [] # same
self.cl_xy = []
self.labels(inline)
for label in self.cl:
self.ax.add_artist(label)
self.label_list = cbook.silent_list('text.Text', self.cl)
return self.label_list
def print_label(self, linecontour,labelwidth):
"if contours are too short, don't plot a label"
lcsize = len(linecontour)
if lcsize > 10 * labelwidth:
return 1
xmax = np.amax(np.array(linecontour)[:,0])
xmin = np.amin(np.array(linecontour)[:,0])
ymax = np.amax(np.array(linecontour)[:,1])
ymin = np.amin(np.array(linecontour)[:,1])
lw = labelwidth
if (xmax - xmin) > 1.2* lw or (ymax - ymin) > 1.2 * lw:
return 1
else:
return 0
def too_close(self, x,y, lw):
"if there's a label already nearby, find a better place"
if self.cl_xy != []:
dist = [np.sqrt((x-loc[0]) ** 2 + (y-loc[1]) ** 2)
for loc in self.cl_xy]
for d in dist:
if d < 1.2*lw:
return 1
else: return 0
else: return 0
00165 def get_label_coords(self, distances, XX, YY, ysize, lw):
""" labels are ploted at a location with the smallest
dispersion of the contour from a straight line
unless there's another label nearby, in which case
the second best place on the contour is picked up
if there's no good place a label isplotted at the
beginning of the contour
"""
hysize = int(ysize/2)
adist = np.argsort(distances)
for ind in adist:
x, y = XX[ind][hysize], YY[ind][hysize]
if self.too_close(x,y, lw):
continue
else:
self.cl_xy.append((x,y))
return x,y, ind
ind = adist[0]
x, y = XX[ind][hysize], YY[ind][hysize]
self.cl_xy.append((x,y))
return x,y, ind
def get_label_width(self, lev, fmt, fsize):
"get the width of the label in points"
if cbook.is_string_like(lev):
lw = (len(lev)) * fsize
else:
lw = (len(fmt%lev)) * fsize
return lw
def set_label_props(self, label, text, color):
"set the label properties - color, fontsize, text"
label.set_text(text)
label.set_color(color)
label.set_fontproperties(self.fp)
label.set_clip_box(self.ax.bbox)
def get_text(self, lev, fmt):
"get the text of the label"
if cbook.is_string_like(lev):
return lev
else:
return fmt%lev
def break_linecontour(self, linecontour, rot, labelwidth, ind):
"break a contour in two contours at the location of the label"
lcsize = len(linecontour)
hlw = int(labelwidth/2)
#length of label in screen coords
ylabel = abs(hlw * np.sin(rot*np.pi/180))
xlabel = abs(hlw * np.cos(rot*np.pi/180))
trans = self.ax.transData
slc = trans.transform(linecontour)
x,y = slc[ind]
xx= np.asarray(slc)[:,0].copy()
yy=np.asarray(slc)[:,1].copy()
#indices which are under the label
inds, = np.nonzero(((xx < x+xlabel) & (xx > x-xlabel)) &
((yy < y+ylabel) & (yy > y-ylabel)))
if len(inds) >0:
#if the label happens to be over the beginning of the
#contour, the entire contour is removed, i.e.
#indices to be removed are
#inds= [0,1,2,3,305,306,307]
#should rewrite this in a better way
linds, = np.nonzero(inds[1:]- inds[:-1] != 1)
if inds[0] == 0 and len(linds) != 0:
ii = inds[linds[0]]
lc1 =linecontour[ii+1:inds[ii+1]]
lc2 = []
else:
lc1=linecontour[:inds[0]]
lc2= linecontour[inds[-1]+1:]
else:
lc1=linecontour[:ind]
lc2 = linecontour[ind+1:]
if rot <0:
new_x1, new_y1 = x-xlabel, y+ylabel
new_x2, new_y2 = x+xlabel, y-ylabel
else:
new_x1, new_y1 = x-xlabel, y-ylabel
new_x2, new_y2 = x+xlabel, y+ylabel
inverse = trans.inverted()
new_x1d, new_y1d = inverse.transform_point((new_x1, new_y1))
new_x2d, new_y2d = inverse.transform_point((new_x2, new_y2))
new_xy1 = np.array(((new_x1d, new_y1d),))
new_xy2 = np.array(((new_x2d, new_y2d),))
if rot > 0:
if (len(lc1) > 0 and (lc1[-1][0] <= new_x1d)
and (lc1[-1][1] <= new_y1d)):
lc1 = np.concatenate((lc1, new_xy1))
#lc1.append((new_x1d, new_y1d))
if (len(lc2) > 0 and (lc2[0][0] >= new_x2d)
and (lc2[0][1] >= new_y2d)):
lc2 = np.concatenate((new_xy2, lc2))
#lc2.insert(0, (new_x2d, new_y2d))
else:
if (len(lc1) > 0 and ((lc1[-1][0] <= new_x1d)
and (lc1[-1][1] >= new_y1d))):
lc1 = np.concatenate((lc1, new_xy1))
#lc1.append((new_x1d, new_y1d))
if (len(lc2) > 0 and ((lc2[0][0] >= new_x2d)
and (lc2[0][1] <= new_y2d))):
lc2 = np.concatenate((new_xy2, lc2))
#lc2.insert(0, (new_x2d, new_y2d))
return [lc1,lc2]
00294 def locate_label(self, linecontour, labelwidth):
"""find a good place to plot a label (relatively flat
part of the contour) and the angle of rotation for the
text object
"""
nsize= len(linecontour)
if labelwidth > 1:
xsize = int(np.ceil(nsize/labelwidth))
else:
xsize = 1
if xsize == 1:
ysize = nsize
else:
ysize = labelwidth
XX = np.resize(np.asarray(linecontour)[:,0],(xsize, ysize))
YY = np.resize(np.asarray(linecontour)[:,1],(xsize, ysize))
#I might have fouled up the following:
yfirst = YY[:,0].reshape(xsize, 1)
ylast = YY[:,-1].reshape(xsize, 1)
xfirst = XX[:,0].reshape(xsize, 1)
xlast = XX[:,-1].reshape(xsize, 1)
s = (yfirst-YY) * (xlast-xfirst) - (xfirst-XX) * (ylast-yfirst)
L = np.sqrt((xlast-xfirst)**2+(ylast-yfirst)**2).ravel()
dist = np.add.reduce(([(abs(s)[i]/L[i]) for i in range(xsize)]),-1)
x,y,ind = self.get_label_coords(dist, XX, YY, ysize, labelwidth)
#print 'ind, x, y', ind, x, y
angle = np.arctan2(ylast - yfirst, xlast - xfirst).ravel()
rotation = angle[ind]*180/np.pi
if rotation > 90:
rotation = rotation -180
if rotation < -90:
rotation = 180 + rotation
# There must be a more efficient way...
lc = [tuple(l) for l in linecontour]
dind = lc.index((x,y))
#print 'dind', dind
#dind = list(linecontour).index((x,y))
return x,y, rotation, dind
def labels(self, inline):
levels = self.label_levels
fslist = self.fslist
trans = self.ax.transData
_colors = self.label_mappable.to_rgba(self.label_cvalues,
alpha=self.alpha)
fmt = self.fmt
for icon, lev, color, cvalue, fsize in zip(self.label_indices,
self.label_levels,
_colors,
self.label_cvalues, fslist):
con = self.collections[icon]
lw = self.get_label_width(lev, fmt, fsize)
additions = []
paths = con.get_paths()
for segNum, linepath in enumerate(paths):
linecontour = linepath.vertices
# for closed contours add one more point to
# avoid division by zero
if np.all(linecontour[0] == linecontour[-1]):
linecontour = np.concatenate((linecontour,
linecontour[1][np.newaxis,:]))
#linecontour.append(linecontour[1])
# transfer all data points to screen coordinates
slc = trans.transform(linecontour)
if self.print_label(slc,lw):
x,y, rotation, ind = self.locate_label(slc, lw)
# transfer the location of the label back to
# data coordinates
dx,dy = trans.inverted().transform_point((x,y))
t = text.Text(dx, dy, rotation = rotation,
horizontalalignment='center',
verticalalignment='center')
_text = self.get_text(lev,fmt)
self.set_label_props(t, _text, color)
self.cl.append(t)
self.cl_cvalues.append(cvalue)
if inline:
new = self.break_linecontour(linecontour, rotation, lw, ind)
if len(new[0]):
paths[segNum] = path.Path(new[0])
if len(new[1]):
additions.append(path.Path(new[1]))
paths.extend(additions)
00383 class ContourSet(cm.ScalarMappable, ContourLabeler):
"""
Create and store a set of contour lines or filled regions.
User-callable method: clabel
Useful attributes:
ax:
the axes object in which the contours are drawn
collections:
a silent_list of LineCollections or PolyCollections
levels:
contour levels
layers:
same as levels for line contours; half-way between
levels for filled contours. See _process_colors method.
"""
00402 def __init__(self, ax, *args, **kwargs):
"""
Draw contour lines or filled regions, depending on
whether keyword arg 'filled' is False (default) or True.
The first argument of the initializer must be an axes
object. The remaining arguments and keyword arguments
are described in ContourSet.contour_doc.
"""
self.ax = ax
self.levels = kwargs.get('levels', None)
self.filled = kwargs.get('filled', False)
self.linewidths = kwargs.get('linewidths', None)
self.linestyles = kwargs.get('linestyles', 'solid')
self.alpha = kwargs.get('alpha', 1.0)
self.origin = kwargs.get('origin', None)
self.extent = kwargs.get('extent', None)
cmap = kwargs.get('cmap', None)
self.colors = kwargs.get('colors', None)
norm = kwargs.get('norm', None)
self.extend = kwargs.get('extend', 'neither')
self.antialiased = kwargs.get('antialiased', True)
self.nchunk = kwargs.get('nchunk', 0)
self.locator = kwargs.get('locator', None)
if (isinstance(norm, colors.LogNorm)
or isinstance(self.locator, ticker.LogLocator)):
self.logscale = True
if norm is None:
norm = colors.LogNorm()
if self.extend is not 'neither':
raise ValueError('extend kwarg does not work yet with log scale')
else:
self.logscale = False
if self.origin is not None: assert(self.origin in
['lower', 'upper', 'image'])
if self.extent is not None: assert(len(self.extent) == 4)
if cmap is not None: assert(isinstance(cmap, colors.Colormap))
if self.colors is not None and cmap is not None:
raise ValueError('Either colors or cmap must be None')
if self.origin == 'image': self.origin = mpl.rcParams['image.origin']
x, y, z = self._contour_args(*args) # also sets self.levels,
# self.layers
if self.colors is not None:
cmap = colors.ListedColormap(self.colors, N=len(self.layers))
if self.filled:
self.collections = cbook.silent_list('collections.PolyCollection')
else:
self.collections = cbook.silent_list('collections.LineCollection')
# label lists must be initialized here
self.cl = []
self.cl_cvalues = []
kw = {'cmap': cmap}
if norm is not None:
kw['norm'] = norm
cm.ScalarMappable.__init__(self, **kw) # sets self.cmap;
self._process_colors()
_mask = ma.getmask(z)
if _mask is ma.nomask:
_mask = None
if self.filled:
if self.linewidths is not None:
warnings.warn('linewidths is ignored by contourf')
C = _cntr.Cntr(x, y, z.filled(), _mask)
lowers = self._levels[:-1]
uppers = self._levels[1:]
for level, level_upper in zip(lowers, uppers):
nlist = C.trace(level, level_upper, points = 0,
nchunk = self.nchunk)
col = collections.PolyCollection(nlist,
antialiaseds = (self.antialiased,),
edgecolors= 'none',
alpha=self.alpha)
self.ax.add_collection(col)
self.collections.append(col)
else:
tlinewidths = self._process_linewidths()
self.tlinewidths = tlinewidths
tlinestyles = self._process_linestyles()
C = _cntr.Cntr(x, y, z.filled(), _mask)
for level, width, lstyle in zip(self.levels, tlinewidths, tlinestyles):
nlist = C.trace(level, points = 0)
col = collections.LineCollection(nlist,
linewidths = width,
linestyle = lstyle,
alpha=self.alpha)
if level < 0.0 and self.monochrome:
ls = mpl.rcParams['contour.negative_linestyle']
col.set_linestyle(ls)
col.set_label('_nolegend_')
self.ax.add_collection(col, False)
self.collections.append(col)
self.changed() # set the colors
x0 = ma.minimum(x)
x1 = ma.maximum(x)
y0 = ma.minimum(y)
y1 = ma.maximum(y)
self.ax.update_datalim([(x0,y0), (x1,y1)])
self.ax.set_xlim((x0, x1))
self.ax.set_ylim((y0, y1))
00509 def changed(self):
tcolors = [ (tuple(rgba),) for rgba in
self.to_rgba(self.cvalues, alpha=self.alpha)]
self.tcolors = tcolors
for color, collection in zip(tcolors, self.collections):
collection.set_alpha(self.alpha)
collection.set_color(color)
for label, cv in zip(self.cl, self.cl_cvalues):
label.set_alpha(self.alpha)
label.set_color(self.label_mappable.to_rgba(cv))
# add label colors
cm.ScalarMappable.changed(self)
00523 def _autolev(self, z, N):
'''
Select contour levels to span the data.
We need two more levels for filled contours than for
line contours, because for the latter we need to specify
the lower and upper boundary of each range. For example,
a single contour boundary, say at z = 0, requires only
one contour line, but two filled regions, and therefore
three levels to provide boundaries for both regions.
'''
if self.locator is None:
if self.logscale:
self.locator = ticker.LogLocator()
else:
self.locator = ticker.MaxNLocator(N+1)
self.locator.create_dummy_axis()
zmax = self.zmax
zmin = self.zmin
self.locator.set_bounds(zmin, zmax)
lev = self.locator()
zmargin = (zmax - zmin) * 0.000001 # so z < (zmax + zmargin)
if zmax >= lev[-1]:
lev[-1] += zmargin
if zmin <= lev[0]:
if self.logscale:
lev[0] = 0.99 * zmin
else:
lev[0] -= zmargin
self._auto = True
if self.filled:
return lev
return lev[1:-1]
00557 def _initialize_x_y(self, z):
'''
Return X, Y arrays such that contour(Z) will match imshow(Z)
if origin is not None.
The center of pixel Z[i,j] depends on origin:
if origin is None, x = j, y = i;
if origin is 'lower', x = j + 0.5, y = i + 0.5;
if origin is 'upper', x = j + 0.5, y = Nrows - i - 0.5
If extent is not None, x and y will be scaled to match,
as in imshow.
If origin is None and extent is not None, then extent
will give the minimum and maximum values of x and y.
'''
if z.ndim != 2:
raise TypeError("Input must be a 2D array.")
else:
Ny, Nx = z.shape
if self.origin is None: # Not for image-matching.
if self.extent is None:
return np.meshgrid(np.arange(Nx), np.arange(Ny))
else:
x0,x1,y0,y1 = self.extent
x = np.linspace(x0, x1, Nx)
y = np.linspace(y0, y1, Ny)
return np.meshgrid(x, y)
# Match image behavior:
if self.extent is None:
x0,x1,y0,y1 = (0, Nx, 0, Ny)
else:
x0,x1,y0,y1 = self.extent
dx = float(x1 - x0)/Nx
dy = float(y1 - y0)/Ny
x = x0 + (np.arange(Nx) + 0.5) * dx
y = y0 + (np.arange(Ny) + 0.5) * dy
if self.origin == 'upper':
y = y[::-1]
return np.meshgrid(x,y)
00595 def _check_xyz(self, args):
'''
For functions like contour, check that the dimensions
of the input arrays match; if x and y are 1D, convert
them to 2D using meshgrid.
Possible change: I think we should make and use an ArgumentError
Exception class (here and elsewhere).
'''
x = np.asarray(args[0], dtype=np.float64)
y = np.asarray(args[1], dtype=np.float64)
z = ma.asarray(args[2], dtype=np.float64)
if z.ndim != 2:
raise TypeError("Input z must be a 2D array.")
else: Ny, Nx = z.shape
if x.shape == z.shape and y.shape == z.shape:
return x,y,z
if x.ndim != 1 or y.ndim != 1:
raise TypeError("Inputs x and y must be 1D or 2D.")
nx, = x.shape
ny, = y.shape
if nx != Nx or ny != Ny:
raise TypeError("Length of x must be number of columns in z,\n" +
"and length of y must be number of rows.")
x,y = np.meshgrid(x,y)
return x,y,z
def _contour_args(self, *args):
if self.filled: fn = 'contourf'
else: fn = 'contour'
Nargs = len(args)
if Nargs <= 2:
z = ma.asarray(args[0], dtype=np.float64)
x, y = self._initialize_x_y(z)
elif Nargs <=4:
x,y,z = self._check_xyz(args[:3])
else:
raise TypeError("Too many arguments to %s; see help(%s)" % (fn,fn))
self.zmax = ma.maximum(z)
self.zmin = ma.minimum(z)
if self.logscale and self.zmin <= 0:
z = ma.masked_where(z <= 0, z)
warnings.warn('Log scale: values of z <=0 have been masked')
self.zmin = z.min()
self._auto = False
if self.levels is None:
if Nargs == 1 or Nargs == 3:
lev = self._autolev(z, 7)
else: # 2 or 4 args
level_arg = args[-1]
try:
if type(level_arg) == int:
lev = self._autolev(z, level_arg)
else:
lev = np.asarray(level_arg).astype(np.float64)
except:
raise TypeError(
"Last %s arg must give levels; see help(%s)" % (fn,fn))
if self.filled and len(lev) < 2:
raise ValueError("Filled contours require at least 2 levels.")
# Workaround for cntr.c bug wrt masked interior regions:
#if filled:
# z = ma.masked_array(z.filled(-1e38))
# It's not clear this is any better than the original bug.
self.levels = lev
#if self._auto and self.extend in ('both', 'min', 'max'):
# raise TypeError("Auto level selection is inconsistent "
# + "with use of 'extend' kwarg")
self._levels = list(self.levels)
if self.extend in ('both', 'min'):
self._levels.insert(0, min(self.levels[0],self.zmin) - 1)
if self.extend in ('both', 'max'):
self._levels.append(max(self.levels[-1],self.zmax) + 1)
self._levels = np.asarray(self._levels)
self.vmin = np.amin(self.levels) # alternative would be self.layers
self.vmax = np.amax(self.levels)
if self.extend in ('both', 'min'):
self.vmin = 2 * self.levels[0] - self.levels[1]
if self.extend in ('both', 'max'):
self.vmax = 2 * self.levels[-1] - self.levels[-2]
self.layers = self._levels # contour: a line is a thin layer
if self.filled:
self.layers = 0.5 * (self._levels[:-1] + self._levels[1:])
if self.extend in ('both', 'min'):
self.layers[0] = 0.5 * (self.vmin + self._levels[1])
if self.extend in ('both', 'max'):
self.layers[-1] = 0.5 * (self.vmax + self._levels[-2])
return (x, y, z)
00687 def _process_colors(self):
"""
Color argument processing for contouring.
Note that we base the color mapping on the contour levels,
not on the actual range of the Z values. This means we
don't have to worry about bad values in Z, and we always have
the full dynamic range available for the selected levels.
The color is based on the midpoint of the layer, except for
an extended end layers.
"""
self.monochrome = self.cmap.monochrome
if self.colors is not None:
i0, i1 = 0, len(self.layers)
if self.extend in ('both', 'min'):
i0 = -1
if self.extend in ('both', 'max'):
i1 = i1 + 1
self.cvalues = range(i0, i1)
self.set_norm(colors.NoNorm())
else:
self.cvalues = self.layers
if not self.norm.scaled():
self.set_clim(self.vmin, self.vmax)
if self.extend in ('both', 'max', 'min'):
self.norm.clip = False
self.set_array(self.layers)
# self.tcolors are set by the "changed" method
def _process_linewidths(self):
linewidths = self.linewidths
Nlev = len(self.levels)
if linewidths is None:
tlinewidths = [(mpl.rcParams['lines.linewidth'],)] *Nlev
else:
if cbook.iterable(linewidths) and len(linewidths) < Nlev:
linewidths = list(linewidths) * int(np.ceil(Nlev/len(linewidths)))
elif not cbook.iterable(linewidths) and type(linewidths) in [int, float]:
linewidths = [linewidths] * Nlev
tlinewidths = [(w,) for w in linewidths]
return tlinewidths
def _process_linestyles(self):
linestyles = self.linestyles
Nlev = len(self.levels)
if linestyles is None:
tlinestyles = ['solid'] * Nlev
else:
if cbook.is_string_like(linestyles):
tlinestyles = [linestyles] * Nlev
elif cbook.iterable(linestyles) and len(linestyles) <= Nlev:
tlinestyles = list(linestyles) * int(np.ceil(Nlev/len(linestyles)))
return tlinestyles
00742 def get_alpha(self):
'''returns alpha to be applied to all ContourSet artists'''
return self.alpha
00746 def set_alpha(self, alpha):
'''sets alpha for all ContourSet artists'''
self.alpha = alpha
self.changed()
contour_doc = """
:func:`~matplotlib.pyplot.contour` and
:func:`~matplotlib.pyplot.contourf` draw contour lines and
filled contours, respectively. Except as noted, function
signatures and return values are the same for both versions.
:func:`~matplotlib.pyplot.contourf` differs from the Matlab
(TM) version in that it does not draw the polygon edges,
because the contouring engine yields simply connected regions
with branch cuts. To draw the edges, add line contours with
calls to :func:`~matplotlib.pyplot.contour`.
call signatures::
contour(Z)
make a contour plot of an array *Z*. The level values are chosen
automatically.
::
contour(X,Y,Z)
*X*, *Y* specify the (*x*, *y*) coordinates of the surface
::
contour(Z,N)
contour(X,Y,Z,N)
contour *N* automatically-chosen levels.
::
contour(Z,V)
contour(X,Y,Z,V)
draw contour lines at the values specified in sequence *V*
::
contourf(..., V)
fill the (len(*V*)-1) regions between the values in *V*
::
contour(Z, **kwargs)
Use keyword args to control colors, linewidth, origin, cmap ... see
below for more details.
*X*, *Y*, and *Z* must be arrays with the same dimensions.
*Z* may be a masked array, but filled contouring may not
handle internal masked regions correctly.
``C = contour(...)`` returns a
:class:`~matplotlib.contour.ContourSet` object.
Optional keyword arguments:
*colors*: [ None | string | (mpl_colors) ]
If *None*, the colormap specified by cmap will be used.
If a string, like 'r' or 'red', all levels will be plotted in this
color.
If a tuple of matplotlib color args (string, float, rgb, etc),
different levels will be plotted in different colors in the order
specified.
*alpha*: float
The alpha blending value
*cmap*: [ None | Colormap ]
A cm :class:`~matplotlib.cm.Colormap` instance or
*None*. If *cmap* is *None* and *colors* is *None*, a
default Colormap is used.
*norm*: [ None | Normalize ]
A :class:`matplotlib.colors.Normalize` instance for
scaling data values to colors. If *norm* is *None* and
*colors* is *None*, the default linear scaling is used.
*origin*: [ None | 'upper' | 'lower' | 'image' ]
If *None*, the first value of *Z* will correspond to the
lower left corner, location (0,0). If 'image', the rc
value for ``image.origin`` will be used.
This keyword is not active if *X* and *Y* are specified in
the call to contour.
*extent*: [ None | (x0,x1,y0,y1) ]
If *origin* is not *None*, then *extent* is interpreted as
in :func:`matplotlib.pyplot.imshow`: it gives the outer
pixel boundaries. In this case, the position of Z[0,0]
is the center of the pixel, not a corner. If *origin* is
*None*, then (*x0*, *y0*) is the position of Z[0,0], and
(*x1*, *y1*) is the position of Z[-1,-1].
This keyword is not active if *X* and *Y* are specified in
the call to contour.
*locator*: [ None | ticker.Locator subclass ]
If *locator* is None, the default
:class:`~matplotlib.ticker.MaxNLocator` is used. The
locator is used to determine the contour levels if they
are not given explicitly via the *V* argument.
*extend*: [ 'neither' | 'both' | 'min' | 'max' ]
Unless this is 'neither', contour levels are automatically
added to one or both ends of the range so that all data
are included. These added ranges are then mapped to the
special colormap values which default to the ends of the
colormap range, but can be set via
:meth:`matplotlib.cm.Colormap.set_under` and
:meth:`matplotlib.cm.Colormap.set_over` methods.
contour-only keyword arguments:
*linewidths*: [ None | number | tuple of numbers ]
If *linewidths* is *None*, the default width in
``lines.linewidth`` in ``matplotlibrc`` is used
If a number, all levels will be plotted with this linewidth.
If a tuple, different levels will be plotted with different
linewidths in the order specified
contourf-only keyword arguments:
*antialiased*: [ True | False ]
enable antialiasing
*nchunk*: [ 0 | integer ]
If 0, no subdivision of the domain. Specify a positive integer to
divide the domain into subdomains of roughly *nchunk* by *nchunk*
points. This may never actually be advantageous, so this option may
be removed. Chunking introduces artifacts at the chunk boundaries
unless *antialiased* is *False*.
"""