DOC: Update the gallery example for pygmt.grdlandmask (#4434)

Author: seisman

examples/gallery/images/grdlandmask.py

@@ -2,8 +2,8 @@
 Create 'wet-dry' mask grid
 ==========================
 
-The :func:`pygmt.grdlandmask` function allows setting all nodes on land
-or water to a specified value using the ``mask_values`` parameter.
+The :func:`pygmt.grdlandmask` function allows setting all nodes on land or water to a
+specified value using the ``mask_values`` parameter.
 """
 
 # %%
@@ -15,22 +15,20 @@
 # Define region of interest
 region = [-65, -40, -40, -20]
 
-# Assign a value of 0 for all water masses and a value of 1 for all land
-# masses.
-# Use shoreline data with (l)ow resolution and set the grid spacing to
-# 5 arc-minutes in x- and y-directions.
+# Assign a value of 0 for all water masses and a value of 1 for all land masses. Use
+# shoreline data with low resolution and set the grid spacing to 5 arc-minutes in x-
+# and y-directions.
 grid = pygmt.grdlandmask(
-    region=region, spacing="5m", mask_values=[0, 1], resolution="l"
+    region=region, spacing="5m", mask_values=[0, 1], resolution="low"
 )
 
 # Plot clipped grid
 fig.basemap(region=region, projection="M12c", frame=True)
 
-# Define a colormap to be used for two categories, define the range of the
-# new discrete CPT using series=(lowest_value, highest_value, interval),
-# use color_model="+cwater,land" to write the discrete color palette
-# "batlow" in categorical format and add water/land as annotations for the
-# colorbar.
+# Define a colormap to be used for two categories, define the range of the new discrete
+# CPT using series=(low, high, interval), use color_model="+cwater,land" to write the
+# discrete color palette "SCM/batlow" in categorical format and add water/land as
+# annotations for the colorbar.
 pygmt.makecpt(cmap="SCM/batlow", series=(0, 1, 1), color_model="+cwater,land")
 
 fig.grdimage(grid=grid, cmap=True)