# NCL_xy_10.py#

This script illustrates the following concepts:
• Filling the area between two curves in an XY plot

• Drawing Greek characters on an XY plot

See following URLs to see the reproduced NCL plot & script:

Import packages:

import numpy as np
import xarray as xr
import matplotlib.pyplot as plt
import math

import geocat.datafiles as gdf
import geocat.viz as gv


# Open a netCDF data file using xarray default engine and load the data into xarrays
ds = xr.open_dataset(gdf.get("netcdf_files/80.nc"))
# Extract slice of data
TS = ds.isel(time=0, lon=21, drop=True).TS


Define bounds for region centered on the data with a width of 2 sigma

nlat = np.shape(TS.lat)[0]
top = np.empty(nlat)
bottom = np.empty(nlat)

for k in range(0, nlat):
dx = math.sqrt(TS[k])
top[k] = TS[k] + dx
bottom[k] = TS[k] - dx


Plot:

plt.figure(figsize=(8, 8))
ax = plt.axes()

# Plot data
TS.plot.line(ax=ax, color='black', _labels=False)

# Plot curves that bound the region to be colored
plt.plot(TS.lat, top, color='SlateBlue')
plt.plot(TS.lat, bottom, color='SlateBlue')

# Fill the area between the bounds
ax.fill_between(TS.lat, top, bottom, color='SlateBlue')

# Use geocat.viz.util convenience function to add minor and major tick lines
x_minor_per_major=3,
y_minor_per_major=4,
labelsize=14)

# Use geocat.viz.util convenience function to set axes parameters
gv.set_axes_limits_and_ticks(
ax,
ylim=(220, 320),
xlim=(-90, 90),
xticks=np.arange(-90, 91, 30),
xticklabels=['90S', '60S', '30S', '0', '30N', '60N', '90N'])

# Use geocat.viz.util convenience function to set titles and labels
gv.set_titles_and_labels(
ax,
maintitle="A Title with $\\eta\epsilon\lambda\\alpha\sigma$ Characters",
ylabel=TS.long_name)

# Draw sigma on axes
ax.text(0.15, 0.15, "$\sigma$", fontsize=40, transform=ax.transAxes)
plt.show()


Total running time of the script: (0 minutes 0.198 seconds)

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