Merge pull request #233 from cbegeman/enhance-tracer-test-viz

Enhance spherical tracer transport test viz

Add options for over/under colors for the colormap used in spherical mpas visualization. These were added to be able to more conveniently visualize over and undershoots in the tracer advection scheme tested in the sphere_transport tests.

docs/developers_guide/framework/visualization.md

@@ -154,7 +154,13 @@ colormap).
 
 The `colorbar_limits` are the lower and upper bound of the colorbar range.
 
+There are also two optional config options used to set the colors on either end of the colormap:
 
+```cfg
+# [optional] colormap set_under and set_over options
+under_color = k
+over_color = orange
+```
 ### plotting from lat/lon grids
 
 You can use {py:func}`polaris.viz.plot_global_lat_lon_field()` to plot a field 

docs/developers_guide/ocean/tasks/correlated_tracers_2d.md

@@ -77,6 +77,10 @@ each resolution.  The colormap is controlled by these options:
 # colormap
 colormap_name = viridis
 
+# [optional] colormap set_under and set_over options
+under_color = k
+over_color = orange
+
 # the type of norm used in the colormap
 norm_type = linear
 

docs/developers_guide/ocean/tasks/divergent_2d.md

@@ -71,6 +71,10 @@ each resolution.  The colormap is controlled by these options:
 # colormap
 colormap_name = viridis
 
+# [optional] colormap set_under and set_over options
+under_color = k
+over_color = orange
+
 # the type of norm used in the colormap
 norm_type = linear
 

docs/developers_guide/ocean/tasks/nondivergent_2d.md

@@ -77,6 +77,10 @@ each resolution.  The colormap is controlled by these options:
 # colormap
 colormap_name = viridis
 
+# [optional] colormap set_under and set_over options
+under_color = k
+over_color = orange
+
 # the type of norm used in the colormap
 norm_type = linear
 

docs/developers_guide/ocean/tasks/rotation_2d.md

@@ -71,6 +71,10 @@ each resolution.  The colormap is controlled by these options:
 # colormap
 colormap_name = viridis
 
+# [optional] colormap set_under and set_over options
+under_color = k
+over_color = orange
+
 # the type of norm used in the colormap
 norm_type = linear
 

polaris/ocean/tasks/sphere_transport/sphere_transport.cfg

@@ -84,6 +84,10 @@ slotted_cylinders_amplitude = 1.0
 # colormap
 colormap_name = viridis
 
+# [optional] colormap set_under and set_over options
+under_color = k
+over_color = orange
+
 # the type of norm used in the colormap
 norm_type = linear
 

polaris/viz/spherical.py

@@ -9,6 +9,7 @@
 import matplotlib.colors as cols
 import matplotlib.pyplot as plt
 import uxarray as ux
+from matplotlib import cm
 from mpl_toolkits.axes_grid1.inset_locator import inset_axes
 from pyremap.descriptor.utility import interp_extrap_corner
 
@@ -81,6 +82,13 @@ def plot_global_mpas_field(mesh_filename, da, out_filename, config,
     projection = cartopy.crs.PlateCarree(central_longitude=central_longitude)
 
     colormap = config.get(colormap_section, 'colormap_name')
+    cmap = cm.get_cmap(colormap)
+    if config.has_option(colormap_section, 'under_color'):
+        under_color = config.get(colormap_section, 'under_color')
+        cmap.set_under(under_color)
+    if config.has_option(colormap_section, 'over_color'):
+        over_color = config.get(colormap_section, 'over_color')
+        cmap.set_over(over_color)
 
     norm_type = config.get(colormap_section, 'norm_type')
     if norm_type == 'linear':
@@ -94,7 +102,7 @@ def plot_global_mpas_field(mesh_filename, da, out_filename, config,
                                      dtype=float)
 
     plot = gdf_data.hvplot.polygons(
-        c=da.name, cmap=colormap, logz=logz,
+        c=da.name, cmap=cmap, logz=logz,
         clim=tuple(colorbar_limits),
         clabel=colorbar_label,
         width=1600, height=800, title=title,