Added a new example to create error boxes using a PatchCollection

tmdavison · tmdavison · commit cd778db53bf0 · 2016-06-16T16:24:01.000+01:00
diff --git a/examples/statistics/errorbars_and_boxes.py b/examples/statistics/errorbars_and_boxes.py
@@ -0,0 +1,48 @@
+import numpy as np
+import matplotlib.pyplot as plt
+from matplotlib.collections import PatchCollection
+from matplotlib.patches import Rectangle
+
+# Number of data points
+n=5
+
+# Dummy data
+x=np.arange(0,n,1)
+y=np.random.rand(n)*5.
+
+# Dummy errors (above and below)
+xerr=np.random.rand(2,n)
+yerr=np.random.rand(2,n)
+
+print xerr[:,0]
+
+# Create figure and axes
+fig,ax = plt.subplots(1)
+
+# Plot data points
+ax.errorbar(x,y,xerr=xerr,yerr=yerr,fmt='None',ecolor='k')
+
+# Function to plot error boxes
+def makeErrorBoxes(xdata,ydata,xerror,yerror,fc='r',ec='None',alpha=0.5):
+
+    # Create list for all the error patches
+    errorboxes = []
+
+    # Loop over data points; create box from errors at each point
+    for xc,yc,xe,ye in zip(xdata,ydata,xerror.T,yerror.T):
+        rect = Rectangle((xc-xe[0],yc-ye[0]),xe.sum(),ye.sum())
+        errorboxes.append(rect)
+
+    # Create patch collection with specified colour/alpha
+    pc = PatchCollection(errorboxes,facecolor=fc,alpha=alpha,edgecolor=ec)
+
+    # Add collection to axes
+    ax.add_collection(pc)
+
+# Call function to create error boxes
+makeErrorBoxes(x,y,xerr,yerr)
+
+# Add some space around the data points on the axes
+ax.margins(0.1)
+
+plt.show()
