# How to plot a heatmap over polar regions using cartopy, matplotlib and python ?

Examples of how to plot a heatmap over polar regions using cartopy, matplotlib and python:

### Plot a heatmap over antarctica using cartopy (example 1)

import cartopy.feature

import matplotlib.path as mpath

fig = plt.figure(figsize=[10, 5])

ax1 = plt.subplot(1, 2, 1, projection=ccrs.SouthPolarStereo())

# Limit the map to -60 degrees latitude and below.
ax1.set_extent([-180, 180, -90, -60], ccrs.PlateCarree())

ax1.gridlines()

theta = np.linspace(0, 2*np.pi, 100)
center, radius = [0.5, 0.5], 0.5
verts = np.vstack([np.sin(theta), np.cos(theta)]).T
circle = mpath.Path(verts * radius + center)

ax1.set_boundary(circle, transform=ax1.transAxes)

plt.savefig("cartopy_antarctica_01.png", bbox_inches='tight', dpi=200)

plt.show()

from cartopy import config
from matplotlib.pyplot import figure

import cartopy.crs as ccrs
import matplotlib.pyplot as plt
import numpy as np

fig = plt.figure(num=None, figsize=(8, 6), dpi=80, edgecolor='k')

ax = plt.axes(projection=ccrs.SouthPolarStereo())

ax.set_extent([-180, 180, -90, -45], ccrs.PlateCarree())

theta = np.linspace(0, 2*np.pi, 200)
center, radius = [0.5, 0.5], 0.5
verts = np.vstack([np.sin(theta), np.cos(theta)]).T
circle = mpath.Path(verts * radius + center)

ax.set_boundary(circle, transform=ax.transAxes)

ax.imshow(data.T, origin='lower', extent=[-180,180,-90,90], transform=ccrs.PlateCarree(),cmap='jet',vmin=0, vmax=1.0)

ax.coastlines()

plt.title("Plot a heatmap with cartopy in python", fontsize=12)

plt.savefig("cartopy_antarctica_03.png", bbox_inches='tight', dpi=200)

plt.show()

### Plot a heatmap over antarctica using cartopy (example 2)

import cartopy.feature

import matplotlib.path as mpath

fig = plt.figure(figsize=[10, 5])

ax1 = plt.subplot(1, 2, 1, projection=ccrs.SouthPolarStereo())

ax1.set_extent([-180, 180, -90, -60], ccrs.PlateCarree())

ax1.gridlines()

plt.savefig("cartopy_antarctica_02.png", bbox_inches='tight', dpi=200)

plt.show()

from cartopy import config
from matplotlib.pyplot import figure

import cartopy.crs as ccrs
import matplotlib.pyplot as plt
import numpy as np

fig = plt.figure(num=None, figsize=(8, 6), dpi=80, edgecolor='k')

ax = plt.axes(projection=ccrs.SouthPolarStereo())

ax.set_extent([-180, 180, -90, -60], ccrs.PlateCarree())

ax.imshow(data.T, origin='lower', extent=[-180,180,-90,90], transform=ccrs.PlateCarree(),cmap='jet',vmin=0, vmax=1.0)

ax.coastlines()

plt.title("Plot a heatmap with cartopy in python", fontsize=12)

plt.savefig("cartopy_antarctica_04.png", bbox_inches='tight', dpi=200)

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