ADD: Colorbar Manipulation Example (#1300)

* ADD: Modify Colorbar Example

* ENH: print statement removal, PEP8 fixes

* ENH: Made Requested Changes

* ENH: Removal of comment lines

* ENH: typo fix

examples/plotting/plot_modify_colorbar.py

@@ -0,0 +1,123 @@
+"""
+=================================
+Modify a Colorbar for your Plot
+=================================
+
+This is an example of how to modify a colobar
+within a Py-ART display object. 
+
+"""
+print(__doc__)
+
+# Author: Joe O'Brien ([email protected])
+# License: BSD 3 clause
+
+import numpy as np
+import matplotlib.pyplot as plt
+import cartopy.crs as ccrs
+
+import pyart
+from pyart.testing import get_test_data
+
+#########################################
+# ** Initial PPI Map Display 
+#
+# Let's plot a PPI Map Display 
+# and take a look at the colorbar
+#
+# Notice: the colorbar is not perfect 
+# and slightly overlaps the PPI display
+
+# Define figure
+fig = plt.figure()
+
+# Create a subplot with correct cartopy projection
+axs = plt.subplot(111, projection=ccrs.PlateCarree())
+
+# Define and Read in the test data
+radar_file = get_test_data('swx_20120520_0641.nc')
+radar = pyart.io.read(radar_file)
+
+# Create the Radar Map Display (defines x,y as lat/lons)
+display = pyart.graph.RadarMapDisplay(radar)
+
+# Display the horizontal equivalent reflectivity factor
+# Note: embellish = False will remove initial lat/lon coords
+display.plot_ppi_map('reflectivity_horizontal',
+                      2,
+                      ax=axs,
+                      vmin=-30,
+                      vmax=60,
+                      embellish=False,
+                      norm=None,
+                      cmap='pyart_HomeyerRainbow')
+
+# Add gridlines
+gl = axs.gridlines(crs=ccrs.PlateCarree(),
+                   draw_labels=True,
+                   linewidth=1, 
+                   color='gray', 
+                   alpha=0.3,
+                   linestyle='--')
+
+plt.gca().xaxis.set_major_locator(plt.NullLocator())
+
+# Make sure labels are only plotted on the left and bottom
+gl.top_labels = False
+gl.right_labels = False
+
+gl.xlabel_style = {'size': 14}
+gl.ylabel_style = {'size': 14}
+
+# delete the display object
+del display
+
+############################################
+# ** Colorbar Position / Title Manipulation
+
+# Now, let's update the colorbar position
+# to match the display
+
+# Define figure
+fig = plt.figure()
+
+# Create a subplot with correct cartopy projection
+axsB = plt.subplot(111, projection=ccrs.PlateCarree())
+
+# Create the Radar Map Display (defines x,y as lat/lons)
+display = pyart.graph.RadarMapDisplay(radar)
+
+# Create the display again 
+ppi_map = display.plot_ppi_map('reflectivity_horizontal',
+                                2,
+                                ax=axsB,
+                                vmin=-30,
+                                vmax=60,
+                                embellish=False,
+                                norm=None,
+                                cmap='pyart_HomeyerRainbow')
+
+# Add gridlines
+gl = axsB.gridlines(crs=ccrs.PlateCarree(),
+                   draw_labels=True,
+                   linewidth=1, 
+                   color='gray', 
+                   alpha=0.3,
+                   linestyle='--')
+
+plt.gca().xaxis.set_major_locator(plt.NullLocator())
+
+# Make sure labels are only plotted on the left and bottom
+gl.top_labels = False
+gl.right_labels = False
+
+# Define the size of the grid labels
+gl.xlabel_style = {'size': 12}
+gl.ylabel_style = {'size': 12}
+
+# Define the colorbar from the RadarMapDisplay object
+cbar = display.cbs[0]
+# Modify the colorbar label and size
+cbar.set_label(label='Horizontal Reflectivity Factor ($Z_{H}$) (dBZ)', fontsize=12)
+# Modify the number of colorbar ticks 
+cbar.set_ticks([-20, 0, 20, 40, 60])