import numpy as np from matplotlib.contour import ContourSet from matplotlib.tri.triangulation import Triangulation class TriContourSet(ContourSet): """ Create and store a set of contour lines or filled regions for a triangular grid. 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. """ def __init__(self, ax, *args, **kwargs): """ Draw triangular grid 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 the docstring of `tricontour`. """ ContourSet.__init__(self, ax, *args, **kwargs) def _process_args(self, *args, **kwargs): """ Process args and kwargs. """ if isinstance(args[0], TriContourSet): C = args[0].cppContourGenerator if self.levels is None: self.levels = args[0].levels else: from matplotlib import _tri tri, z = self._contour_args(args, kwargs) C = _tri.TriContourGenerator(tri.get_cpp_triangulation(), z) self._mins = [tri.x.min(), tri.y.min()] self._maxs = [tri.x.max(), tri.y.max()] self.cppContourGenerator = C return kwargs def _get_allsegs_and_allkinds(self): """ Create and return allsegs and allkinds by calling underlying C code. """ allsegs = [] if self.filled: lowers, uppers = self._get_lowers_and_uppers() allkinds = [] for lower, upper in zip(lowers, uppers): segs, kinds = self.cppContourGenerator.create_filled_contour( lower, upper) allsegs.append([segs]) allkinds.append([kinds]) else: allkinds = None for level in self.levels: segs = self.cppContourGenerator.create_contour(level) allsegs.append(segs) return allsegs, allkinds def _contour_args(self, args, kwargs): if self.filled: fn = 'contourf' else: fn = 'contour' tri, args, kwargs = Triangulation.get_from_args_and_kwargs(*args, **kwargs) z = np.ma.asarray(args[0]) if z.shape != tri.x.shape: raise ValueError('z array must have same length as triangulation x' ' and y arrays') # z values must be finite, only need to check points that are included # in the triangulation. z_check = z[np.unique(tri.get_masked_triangles())] if np.ma.is_masked(z_check): raise ValueError('z must not contain masked points within the ' 'triangulation') if not np.isfinite(z_check).all(): raise ValueError('z array must not contain non-finite values ' 'within the triangulation') z = np.ma.masked_invalid(z, copy=False) self.zmax = float(z_check.max()) self.zmin = float(z_check.min()) if self.logscale and self.zmin <= 0: raise ValueError('Cannot %s log of negative values.' % fn) self._contour_level_args(z, args[1:]) return (tri, z) def tricontour(ax, *args, **kwargs): """ Draw contours on an unstructured triangular grid. `.tricontour` and `.tricontourf` draw contour lines and filled contours, respectively. Except as noted, function signatures and return values are the same for both versions. The triangulation can be specified in one of two ways; either :: tricontour(triangulation, ...) where *triangulation* is a `matplotlib.tri.Triangulation` object, or :: tricontour(x, y, ...) tricontour(x, y, triangles, ...) tricontour(x, y, triangles=triangles, ...) tricontour(x, y, mask=mask, ...) tricontour(x, y, triangles, mask=mask, ...) in which case a `.Triangulation` object will be created. See that class' docstring for an explanation of these cases. The remaining arguments may be:: tricontour(..., Z) where *Z* is the array of values to contour, one per point in the triangulation. The level values are chosen automatically. :: tricontour(..., Z, N) contour up to *N+1* automatically chosen contour levels (*N* intervals). :: tricontour(..., Z, V) draw contour lines at the values specified in sequence *V*, which must be in increasing order. :: tricontourf(..., Z, V) fill the (len(*V*)-1) regions between the values in *V*, which must be in increasing order. :: tricontour(Z, **kwargs) Use keyword args to control colors, linewidth, origin, cmap ... see below for more details. `.tricontour(...)` returns a `~matplotlib.contour.TriContourSet` 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.colors.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. *levels* [level0, level1, ..., leveln] A list of floating point numbers indicating the level curves to draw, in increasing order; e.g., to draw just the zero contour pass ``levels=[0]`` *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.colors.Colormap.set_under` and :meth:`matplotlib.colors.Colormap.set_over` methods. *xunits*, *yunits*: [ *None* | registered units ] Override axis units by specifying an instance of a :class:`matplotlib.units.ConversionInterface`. tricontour-only keyword arguments: *linewidths*: [ *None* | number | tuple of numbers ] If *linewidths* is *None*, defaults to rc:`lines.linewidth`. 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 *linestyles*: [ *None* | 'solid' | 'dashed' | 'dashdot' | 'dotted' ] If *linestyles* is *None*, the 'solid' is used. *linestyles* can also be an iterable of the above strings specifying a set of linestyles to be used. If this iterable is shorter than the number of contour levels it will be repeated as necessary. If contour is using a monochrome colormap and the contour level is less than 0, then the linestyle specified in :rc:`contour.negative_linestyle` will be used. tricontourf-only keyword arguments: *antialiased*: bool enable antialiasing Note: `.tricontourf` fills intervals that are closed at the top; that is, for boundaries *z1* and *z2*, the filled region is:: z1 < Z <= z2 except for the lowest interval, which is closed on both sides (i.e. it includes the lowest value). """ kwargs['filled'] = False return TriContourSet(ax, *args, **kwargs) def tricontourf(ax, *args, **kwargs): kwargs['filled'] = True return TriContourSet(ax, *args, **kwargs) tricontourf.__doc__ = tricontour.__doc__