Source code for

import numpy as np

from . import utils

[docs]def dot_plot(points, intervals=None, lines=None, sections=None, styles=None, marker_props=None, line_props=None, split_names=None, section_order=None, line_order=None, stacked=False, styles_order=None, striped=False, horizontal=True, show_names="both", fmt_left_name=None, fmt_right_name=None, show_section_titles=None, ax=None): """ Dot plotting (also known as forest and blobbogram). Produce a dotplot similar in style to those in Cleveland's "Visualizing Data" book ([1]_). These are also known as "forest plots". Parameters ---------- points : array_like The quantitative values to be plotted as markers. intervals : array_like The intervals to be plotted around the points. The elements of `intervals` are either scalars or sequences of length 2. A scalar indicates the half width of a symmetric interval. A sequence of length 2 contains the left and right half-widths (respectively) of a nonsymmetric interval. If None, no intervals are drawn. lines : array_like A grouping variable indicating which points/intervals are drawn on a common line. If None, each point/interval appears on its own line. sections : array_like A grouping variable indicating which lines are grouped into sections. If None, everything is drawn in a single section. styles : array_like A grouping label defining the plotting style of the markers and intervals. marker_props : dict A dictionary mapping style codes (the values in `styles`) to dictionaries defining key/value pairs to be passed as keyword arguments to `plot` when plotting markers. Useful keyword arguments are "color", "marker", and "ms" (marker size). line_props : dict A dictionary mapping style codes (the values in `styles`) to dictionaries defining key/value pairs to be passed as keyword arguments to `plot` when plotting interval lines. Useful keyword arguments are "color", "linestyle", "solid_capstyle", and "linewidth". split_names : str If not None, this is used to split the values of `lines` into substrings that are drawn in the left and right margins, respectively. If None, the values of `lines` are drawn in the left margin. section_order : array_like The section labels in the order in which they appear in the dotplot. line_order : array_like The line labels in the order in which they appear in the dotplot. stacked : bool If True, when multiple points or intervals are drawn on the same line, they are offset from each other. styles_order : array_like If stacked=True, this is the order in which the point styles on a given line are drawn from top to bottom (if horizontal is True) or from left to right (if horizontal is False). If None (default), the order is lexical. striped : bool If True, every other line is enclosed in a shaded box. horizontal : bool If True (default), the lines are drawn horizontally, otherwise they are drawn vertically. show_names : str Determines whether labels (names) are shown in the left and/or right margins (top/bottom margins if `horizontal` is True). If `both`, labels are drawn in both margins, if 'left', labels are drawn in the left or top margin. If `right`, labels are drawn in the right or bottom margin. fmt_left_name : callable The left/top margin names are passed through this function before drawing on the plot. fmt_right_name : callable The right/bottom marginnames are passed through this function before drawing on the plot. show_section_titles : bool or None If None, section titles are drawn only if there is more than one section. If False/True, section titles are never/always drawn, respectively. ax : matplotlib.axes The axes on which the dotplot is drawn. If None, a new axes is created. Returns ------- fig : Figure The figure given by `ax.figure` or a new instance. Notes ----- `points`, `intervals`, `lines`, `sections`, `styles` must all have the same length whenever present. References ---------- .. [1] Cleveland, William S. (1993). "Visualizing Data". Hobart Press. .. [2] Jacoby, William G. (2006) "The Dot Plot: A Graphical Display for Labeled Quantitative Values." The Political Methodologist 14(1): 6-14. Examples -------- This is a simple dotplot with one point per line: >>> dot_plot(points=point_values) This dotplot has labels on the lines (if elements in `label_values` are repeated, the corresponding points appear on the same line): >>> dot_plot(points=point_values, lines=label_values) """ import matplotlib.transforms as transforms fig, ax = utils.create_mpl_ax(ax) # Convert to numpy arrays if that is not what we are given. points = np.asarray(points) asarray_or_none = lambda x : None if x is None else np.asarray(x) intervals = asarray_or_none(intervals) lines = asarray_or_none(lines) sections = asarray_or_none(sections) styles = asarray_or_none(styles) # Total number of points npoint = len(points) # Set default line values if needed if lines is None: lines = np.arange(npoint) # Set default section values if needed if sections is None: sections = np.zeros(npoint) # Set default style values if needed if styles is None: styles = np.zeros(npoint) # The vertical space (in inches) for a section title section_title_space = 0.5 # The number of sections nsect = len(set(sections)) if section_order is not None: nsect = len(set(section_order)) # The number of section titles if show_section_titles is False: draw_section_titles = False nsect_title = 0 elif show_section_titles is True: draw_section_titles = True nsect_title = nsect else: draw_section_titles = nsect > 1 nsect_title = nsect if nsect > 1 else 0 # The total vertical space devoted to section titles. section_space_total = section_title_space * nsect_title # Add a bit of room so that points that fall at the axis limits # are not cut in half. ax.set_xmargin(0.02) ax.set_ymargin(0.02) if section_order is None: lines0 = list(set(sections)) lines0.sort() else: lines0 = section_order if line_order is None: lines1 = list(set(lines)) lines1.sort() else: lines1 = line_order # A map from (section,line) codes to index positions. lines_map = {} for i in range(npoint): if section_order is not None and sections[i] not in section_order: continue if line_order is not None and lines[i] not in line_order: continue ky = (sections[i], lines[i]) if ky not in lines_map: lines_map[ky] = [] lines_map[ky].append(i) # Get the size of the axes on the parent figure in inches bbox = ax.get_window_extent().transformed( fig.dpi_scale_trans.inverted()) awidth, aheight = bbox.width, bbox.height # The number of lines in the plot. nrows = len(lines_map) # The positions of the lowest and highest guideline in axes # coordinates (for horizontal dotplots), or the leftmost and # rightmost guidelines (for vertical dotplots). bottom, top = 0, 1 if horizontal: # x coordinate is data, y coordinate is axes trans = transforms.blended_transform_factory(ax.transData, ax.transAxes) else: # x coordinate is axes, y coordinate is data trans = transforms.blended_transform_factory(ax.transAxes, ax.transData) # Space used for a section title, in axes coordinates title_space_axes = section_title_space / aheight # Space between lines if horizontal: dpos = (top - bottom - nsect_title*title_space_axes) /\ float(nrows) else: dpos = (top - bottom) / float(nrows) # Determine the spacing for stacked points if styles_order is not None: style_codes = styles_order else: style_codes = list(set(styles)) style_codes.sort() # Order is top to bottom for horizontal plots, so need to # flip. if horizontal: style_codes = style_codes[::-1] # nval is the maximum number of points on one line. nval = len(style_codes) if nval > 1: stackd = dpos / (2.5*(float(nval)-1)) else: stackd = 0. # Map from style code to its integer position style_codes_map = {x: style_codes.index(x) for x in style_codes} # Setup default marker styles colors = ["r", "g", "b", "y", "k", "purple", "orange"] if marker_props is None: marker_props = {x: {} for x in style_codes} for j in range(nval): sc = style_codes[j] if "color" not in marker_props[sc]: marker_props[sc]["color"] = colors[j % len(colors)] if "marker" not in marker_props[sc]: marker_props[sc]["marker"] = "o" if "ms" not in marker_props[sc]: marker_props[sc]["ms"] = 10 if stackd == 0 else 6 # Setup default line styles if line_props is None: line_props = {x: {} for x in style_codes} for j in range(nval): sc = style_codes[j] if "color" not in line_props[sc]: line_props[sc]["color"] = "grey" if "linewidth" not in line_props[sc]: line_props[sc]["linewidth"] = 2 if stackd > 0 else 8 if horizontal: # The vertical position of the first line. pos = top - dpos/2 if nsect == 1 else top else: # The horizontal position of the first line. pos = bottom + dpos/2 # Points that have already been labeled labeled = set() # Positions of the y axis grid lines ticks = [] # Loop through the sections for k0 in lines0: # Draw a section title if draw_section_titles: if horizontal: y0 = pos + dpos/2 if k0 == lines0[0] else pos ax.fill_between((0, 1), (y0,y0), (pos-0.7*title_space_axes, pos-0.7*title_space_axes), color='darkgrey', transform=ax.transAxes, zorder=1) txt = ax.text(0.5, pos - 0.35*title_space_axes, k0, horizontalalignment='center', verticalalignment='center', transform=ax.transAxes) txt.set_fontweight("bold") pos -= title_space_axes else: m = len([k for k in lines_map if k[0] == k0]) ax.fill_between((pos-dpos/2+0.01, pos+(m-1)*dpos+dpos/2-0.01), (1.01,1.01), (1.06,1.06), color='darkgrey', transform=ax.transAxes, zorder=1, clip_on=False) txt = ax.text(pos + (m-1)*dpos/2, 1.02, k0, horizontalalignment='center', verticalalignment='bottom', transform=ax.transAxes) txt.set_fontweight("bold") jrow = 0 for k1 in lines1: # No data to plot if (k0, k1) not in lines_map: continue # Draw the guideline if horizontal: ax.axhline(pos, color='grey') else: ax.axvline(pos, color='grey') # Set up the labels if split_names is not None: us = k1.split(split_names) if len(us) >= 2: left_label, right_label = us[0], us[1] else: left_label, right_label = k1, None else: left_label, right_label = k1, None if fmt_left_name is not None: left_label = fmt_left_name(left_label) if fmt_right_name is not None: right_label = fmt_right_name(right_label) # Draw the stripe if striped and jrow % 2 == 0: if horizontal: ax.fill_between((0, 1), (pos-dpos/2, pos-dpos/2), (pos+dpos/2, pos+dpos/2), color='lightgrey', transform=ax.transAxes, zorder=0) else: ax.fill_between((pos-dpos/2, pos+dpos/2), (0, 0), (1, 1), color='lightgrey', transform=ax.transAxes, zorder=0) jrow += 1 # Draw the left margin label if show_names.lower() in ("left", "both"): if horizontal: ax.text(-0.1/awidth, pos, left_label, horizontalalignment="right", verticalalignment='center', transform=ax.transAxes, family='monospace') else: ax.text(pos, -0.1/aheight, left_label, horizontalalignment="center", verticalalignment='top', transform=ax.transAxes, family='monospace') # Draw the right margin label if show_names.lower() in ("right", "both"): if right_label is not None: if horizontal: ax.text(1 + 0.1/awidth, pos, right_label, horizontalalignment="left", verticalalignment='center', transform=ax.transAxes, family='monospace') else: ax.text(pos, 1 + 0.1/aheight, right_label, horizontalalignment="center", verticalalignment='bottom', transform=ax.transAxes, family='monospace') # Save the vertical position so that we can place the # tick marks ticks.append(pos) # Loop over the points in one line for ji,jp in enumerate(lines_map[(k0,k1)]): # Calculate the vertical offset yo = 0 if stacked: yo = -dpos/5 + style_codes_map[styles[jp]]*stackd pt = points[jp] # Plot the interval if intervals is not None: # Symmetric interval if np.isscalar(intervals[jp]): lcb, ucb = pt - intervals[jp],\ pt + intervals[jp] # Nonsymmetric interval else: lcb, ucb = pt - intervals[jp][0],\ pt + intervals[jp][1] # Draw the interval if horizontal: ax.plot([lcb, ucb], [pos+yo, pos+yo], '-', transform=trans, **line_props[styles[jp]]) else: ax.plot([pos+yo, pos+yo], [lcb, ucb], '-', transform=trans, **line_props[styles[jp]]) # Plot the point sl = styles[jp] sll = sl if sl not in labeled else None labeled.add(sl) if horizontal: ax.plot([pt,], [pos+yo,], ls='None', transform=trans, label=sll, **marker_props[sl]) else: ax.plot([pos+yo,], [pt,], ls='None', transform=trans, label=sll, **marker_props[sl]) if horizontal: pos -= dpos else: pos += dpos # Set up the axis if horizontal: ax.xaxis.set_ticks_position("bottom") ax.yaxis.set_ticks_position("none") ax.set_yticklabels([]) ax.spines['left'].set_color('none') ax.spines['right'].set_color('none') ax.spines['top'].set_color('none') ax.spines['bottom'].set_position(('axes', -0.1/aheight)) ax.set_ylim(0, 1) ax.yaxis.set_ticks(ticks) ax.autoscale_view(scaley=False, tight=True) else: ax.yaxis.set_ticks_position("left") ax.xaxis.set_ticks_position("none") ax.set_xticklabels([]) ax.spines['bottom'].set_color('none') ax.spines['right'].set_color('none') ax.spines['top'].set_color('none') ax.spines['left'].set_position(('axes', -0.1/awidth)) ax.set_xlim(0, 1) ax.xaxis.set_ticks(ticks) ax.autoscale_view(scalex=False, tight=True) return fig