Merge pull request matplotlib#2452 from larrybradley/limitfix

Fixed issues with errorbar limits

Author: tacaswell

doc/api/api_changes.rst

@@ -47,6 +47,10 @@ original location:
   - mstream -> `from matplotlib import stream as mstream`
   - mtable -> `from matplotlib import table as mtable`
 
+* The :func:`~matplotlib.pyplot.errorbar` method has been changed such that
+  the upper and lower limits (*lolims*, *uplims*, *xlolims*, *xuplims*) now
+  point in the correct direction.
+
 * The Sphinx extensions `ipython_directive` and
   `ipython_console_highlighting` have been moved to the IPython
   project itself.  While they remain in matplotlib for this release,

doc/users/whats_new.rst

@@ -139,6 +139,11 @@ specify wedgeprops = {'linewidth':3} to specify the width of the borders of
 the wedges in the pie. For more properties that the user can specify, look at
 the docs for the wedge and text objects.
 
+Fixed the direction of errorbar upper/lower limits
+``````````````````````````````````````````````````
+Larry Bradley fixed the :func:`~matplotlib.pyplot.errorbar` method such
+that the upper and lower limits (*lolims*, *uplims*, *xlolims*,
+*xuplims*) now point in the correct direction.
 
 Date handling
 -------------

examples/statistics/errorbar_limits.py

@@ -0,0 +1,53 @@
+"""
+Demo of the errorbar function, including upper and lower limits
+"""
+import numpy as np
+import matplotlib.pyplot as plt
+
+# example data
+x = np.arange(0.5, 5.5, 0.5)
+y = np.exp(-x)
+xerr = 0.1
+yerr = 0.2
+ls = 'dotted'
+
+fig = plt.figure()
+ax = fig.add_subplot(1, 1, 1)
+
+# standard error bars
+plt.errorbar(x, y, xerr=xerr, yerr=yerr, ls=ls, color='blue')
+
+# including upper limits
+uplims = np.zeros(x.shape)
+uplims[[1, 5, 9]] = True
+plt.errorbar(x, y+0.5, xerr=xerr, yerr=yerr, uplims=uplims, ls=ls,
+             color='green')
+
+# including lower limits
+lolims = np.zeros(x.shape)
+lolims[[2, 4, 8]] = True
+plt.errorbar(x, y+1.0, xerr=xerr, yerr=yerr, lolims=lolims, ls=ls,
+             color='red')
+
+# including upper and lower limits
+plt.errorbar(x, y+1.5, marker='o', ms=8, xerr=xerr, yerr=yerr,
+             lolims=lolims, uplims=uplims, ls=ls, color='magenta')
+
+# including xlower and xupper limits
+xerr = 0.2
+yerr = np.zeros(x.shape) + 0.2
+yerr[[3, 6]] = 0.3
+xlolims = lolims
+xuplims = uplims
+lolims = np.zeros(x.shape)
+uplims = np.zeros(x.shape)
+lolims[[6]] = True
+uplims[[3]] = True
+plt.errorbar(x, y+2.1, marker='o', ms=8, xerr=xerr, yerr=yerr,
+             xlolims=xlolims, xuplims=xuplims, uplims=uplims, lolims=lolims,
+             ls='none', mec='blue', capsize=0, color='cyan')
+
+ax.set_xlim((0, 5.5))
+ax.set_title('Errorbar upper and lower limits')
+plt.show()
+

lib/matplotlib/axes/_axes.py

@@ -2602,7 +2602,9 @@ def errorbar(self, x, y, yerr=None, xerr=None,
             These arguments can be used to indicate that a value gives
             only upper/lower limits. In that case a caret symbol is
             used to indicate this. lims-arguments may be of the same
-            type as *xerr* and *yerr*.
+            type as *xerr* and *yerr*.  To use limits with inverted
+            axes, :meth:`set_xlim` or :meth:`set_ylim` must be called
+            before :meth:`errorbar`.
 
           *errorevery*: positive integer
             subsamples the errorbars. e.g., if everyerror=5, errorbars for
@@ -2682,16 +2684,12 @@ def errorbar(self, x, y, yerr=None, xerr=None,
         if elinewidth:
             lines_kw['linewidth'] = elinewidth
         else:
-            if 'linewidth' in kwargs:
-                lines_kw['linewidth'] = kwargs['linewidth']
-            if 'lw' in kwargs:
-                lines_kw['lw'] = kwargs['lw']
-        if 'transform' in kwargs:
-            lines_kw['transform'] = kwargs['transform']
-        if 'alpha' in kwargs:
-            lines_kw['alpha'] = kwargs['alpha']
-        if 'zorder' in kwargs:
-            lines_kw['zorder'] = kwargs['zorder']
+            for key in ('linewidth', 'lw'):
+                if key in kwargs:
+                    lines_kw[key] = kwargs[key]
+        for key in ('transform', 'alpha', 'zorder'):
+            if key in kwargs:
+                lines_kw[key] = kwargs[key]
 
         # arrays fine here, they are booleans and hence not units
         if not iterable(lolims):
@@ -2727,29 +2725,21 @@ def xywhere(xs, ys, mask):
             ys = [thisy for thisy, b in zip(ys, mask) if b]
             return xs, ys
 
+        plot_kw = {'label': '_nolegend_'}
         if capsize > 0:
-            plot_kw = {
-                'ms': 2 * capsize,
-                'label': '_nolegend_'}
-            if capthick is not None:
-                # 'mew' has higher priority, I believe,
-                # if both 'mew' and 'markeredgewidth' exists.
-                # So, save capthick to markeredgewidth so that
-                # explicitly setting mew or markeredgewidth will
-                # over-write capthick.
-                plot_kw['markeredgewidth'] = capthick
-            # For backwards-compat, allow explicit setting of
-            # 'mew' or 'markeredgewidth' to over-ride capthick.
-            if 'markeredgewidth' in kwargs:
-                plot_kw['markeredgewidth'] = kwargs['markeredgewidth']
-            if 'mew' in kwargs:
-                plot_kw['mew'] = kwargs['mew']
-            if 'transform' in kwargs:
-                plot_kw['transform'] = kwargs['transform']
-            if 'alpha' in kwargs:
-                plot_kw['alpha'] = kwargs['alpha']
-            if 'zorder' in kwargs:
-                plot_kw['zorder'] = kwargs['zorder']
+            plot_kw['ms'] = 2. * capsize
+        if capthick is not None:
+            # 'mew' has higher priority, I believe,
+            # if both 'mew' and 'markeredgewidth' exists.
+            # So, save capthick to markeredgewidth so that
+            # explicitly setting mew or markeredgewidth will
+            # over-write capthick.
+            plot_kw['markeredgewidth'] = capthick
+        # For backwards-compat, allow explicit setting of
+        # 'mew' or 'markeredgewidth' to over-ride capthick.
+        for key in ('markeredgewidth', 'mew', 'transform', 'alpha', 'zorder'):
+            if key in kwargs:
+                plot_kw[key] = kwargs[key]
 
         if xerr is not None:
             if (iterable(xerr) and len(xerr) == 2 and
@@ -2766,38 +2756,48 @@ def xywhere(xs, ys, mask):
                 right = [thisx + thiserr for (thisx, thiserr)
                          in cbook.safezip(x, xerr)]
 
-            yo, _ = xywhere(y, right, everymask)
-            lo, ro = xywhere(left, right, everymask)
-            barcols.append(self.hlines(yo, lo, ro, **lines_kw))
-            if capsize > 0:
-                if xlolims.any():
-                    # can't use numpy logical indexing since left and
-                    # y are lists
-                    leftlo, ylo = xywhere(left, y, xlolims & everymask)
-
-                    caplines.extend(
-                        self.plot(leftlo, ylo, ls='None',
-                                  marker=mlines.CARETLEFT, **plot_kw))
-                    xlolims = ~xlolims
-                    leftlo, ylo = xywhere(left, y, xlolims & everymask)
-                    caplines.extend(self.plot(leftlo, ylo, 'k|', **plot_kw))
+            # select points without upper/lower limits in x and
+            # draw normal errorbars for these points
+            noxlims = ~(xlolims | xuplims)
+            if noxlims.any():
+                yo, _ = xywhere(y, right, noxlims & everymask)
+                lo, ro = xywhere(left, right, noxlims & everymask)
+                barcols.append(self.hlines(yo, lo, ro, **lines_kw))
+                if capsize > 0:
+                    caplines.extend(self.plot(lo, yo, 'k|', **plot_kw))
+                    caplines.extend(self.plot(ro, yo, 'k|', **plot_kw))
+
+            if xlolims.any():
+                yo, _ = xywhere(y, right, xlolims & everymask)
+                lo, ro = xywhere(x, right, xlolims & everymask)
+                barcols.append(self.hlines(yo, lo, ro, **lines_kw))
+                rightup, yup = xywhere(right, y, xlolims & everymask)
+                if self.xaxis_inverted():
+                    marker = mlines.CARETLEFT
                 else:
-
-                    leftlo, ylo = xywhere(left, y, everymask)
-                    caplines.extend(self.plot(leftlo, ylo, 'k|', **plot_kw))
-
-                if xuplims.any():
-
-                    rightup, yup = xywhere(right, y, xuplims & everymask)
-                    caplines.extend(
-                        self.plot(rightup, yup, ls='None',
-                                  marker=mlines.CARETRIGHT, **plot_kw))
-                    xuplims = ~xuplims
-                    rightup, yup = xywhere(right, y, xuplims & everymask)
-                    caplines.extend(self.plot(rightup, yup, 'k|', **plot_kw))
+                    marker = mlines.CARETRIGHT
+                caplines.extend(
+                    self.plot(rightup, yup, ls='None', marker=marker,
+                              **plot_kw))
+                if capsize > 0:
+                    xlo, ylo = xywhere(x, y, xlolims & everymask)
+                    caplines.extend(self.plot(xlo, ylo, 'k|', **plot_kw))
+
+            if xuplims.any():
+                yo, _ = xywhere(y, right, xuplims & everymask)
+                lo, ro = xywhere(left, x, xuplims & everymask)
+                barcols.append(self.hlines(yo, lo, ro, **lines_kw))
+                leftlo, ylo = xywhere(left, y, xuplims & everymask)
+                if self.xaxis_inverted():
+                    marker = mlines.CARETRIGHT
                 else:
-                    rightup, yup = xywhere(right, y, everymask)
-                    caplines.extend(self.plot(rightup, yup, 'k|', **plot_kw))
+                    marker = mlines.CARETLEFT
+                caplines.extend(
+                    self.plot(leftlo,  ylo, ls='None', marker=marker,
+                              **plot_kw))
+                if capsize > 0:
+                    xup, yup = xywhere(x, y, xuplims & everymask)
+                    caplines.extend(self.plot(xup, yup, 'k|', **plot_kw))
 
         if yerr is not None:
             if (iterable(yerr) and len(yerr) == 2 and
@@ -2814,35 +2814,48 @@ def xywhere(xs, ys, mask):
                 upper = [thisy + thiserr for (thisy, thiserr)
                          in cbook.safezip(y, yerr)]
 
-            xo, _ = xywhere(x, lower, everymask)
-            lo, uo = xywhere(lower, upper, everymask)
-            barcols.append(self.vlines(xo, lo, uo, **lines_kw))
-            if capsize > 0:
-
-                if lolims.any():
-                    xlo, lowerlo = xywhere(x, lower, lolims & everymask)
-                    caplines.extend(
-                        self.plot(xlo, lowerlo, ls='None',
-                                  marker=mlines.CARETDOWN, **plot_kw))
-                    lolims = ~lolims
-                    xlo, lowerlo = xywhere(x, lower, lolims & everymask)
-                    caplines.extend(self.plot(xlo, lowerlo, 'k_', **plot_kw))
+            # select points without upper/lower limits in y and
+            # draw normal errorbars for these points
+            noylims = ~(lolims | uplims)
+            if noylims.any():
+                xo, _ = xywhere(x, lower, noylims & everymask)
+                lo, uo = xywhere(lower, upper, noylims & everymask)
+                barcols.append(self.vlines(xo, lo, uo, **lines_kw))
+                if capsize > 0:
+                    caplines.extend(self.plot(xo, lo, 'k_', **plot_kw))
+                    caplines.extend(self.plot(xo, uo, 'k_', **plot_kw))
+
+            if lolims.any():
+                xo, _ = xywhere(x, lower, lolims & everymask)
+                lo, uo = xywhere(y, upper, lolims & everymask)
+                barcols.append(self.vlines(xo, lo, uo, **lines_kw))
+                xup, upperup = xywhere(x, upper, lolims & everymask)
+                if self.yaxis_inverted():
+                    marker = mlines.CARETDOWN
                 else:
-                    xlo, lowerlo = xywhere(x, lower, everymask)
-                    caplines.extend(self.plot(xlo, lowerlo, 'k_', **plot_kw))
-
-                if uplims.any():
-                    xup, upperup = xywhere(x, upper, uplims & everymask)
-
-                    caplines.extend(
-                        self.plot(xup, upperup, ls='None',
-                                  marker=mlines.CARETUP, **plot_kw))
-                    uplims = ~uplims
-                    xup, upperup = xywhere(x, upper, uplims & everymask)
-                    caplines.extend(self.plot(xup, upperup, 'k_', **plot_kw))
+                    marker = mlines.CARETUP
+                caplines.extend(
+                    self.plot(xup, upperup, ls='None', marker=marker,
+                              **plot_kw))
+                if capsize > 0:
+                    xlo, ylo = xywhere(x, y, lolims & everymask)
+                    caplines.extend(self.plot(xlo, ylo, 'k_', **plot_kw))
+
+            if uplims.any():
+                xo, _ = xywhere(x, lower, uplims & everymask)
+                lo, uo = xywhere(lower, y, uplims & everymask)
+                barcols.append(self.vlines(xo, lo, uo, **lines_kw))
+                xlo, lowerlo = xywhere(x, lower, uplims & everymask)
+                if self.yaxis_inverted():
+                    marker = mlines.CARETUP
                 else:
-                    xup, upperup = xywhere(x, upper, everymask)
-                    caplines.extend(self.plot(xup, upperup, 'k_', **plot_kw))
+                    marker = mlines.CARETDOWN
+                caplines.extend(
+                    self.plot(xlo, lowerlo, ls='None', marker=marker,
+                              **plot_kw))
+                if capsize > 0:
+                    xup, yup = xywhere(x, y, uplims & everymask)
+                    caplines.extend(self.plot(xup, yup, 'k_', **plot_kw))
 
         if not barsabove and fmt is not None:
             l0, = self.plot(x, y, fmt, **kwargs)