background image interpolation with caryopy

Question

Recently I updated to matplotlib 3.3.1 on python 3.8. I use cartopy version 0.18.0. With this version, the background image interpolation seems to work anymore. Does anyone have a workaround/soultion? Here is a minimum reproducible example:

import matplotlib.pyplot as plt
import cartopy as ccrs
import cartopy.io.img_tiles as cimgt

fig, ax = plt.subplots(subplot_kw=dict(projection=ccrs.crs.PlateCarree()))
ax.set_extent([67, 75, 20, 26])
ax.add_image(cimgt.GoogleTiles(), 8, interpolation='spline36')

Which throws an error:

TypeError: got an unexpected keyword argument 'interpolation'

Answer 1

If you need better resolution images, you need to increase the scale value. In your code, you can change 8 to 10 as a new experiment.

ax.add_image(cimgt.GoogleTiles(), 10)

Edit1

Since the use of projection (crs.PlateCarree()) different from the original (crs.Mercator()) causes the image's reprojection at the time of rendering, and results in unsatisfactory image quality. And this type of images, with sharp edges/lines, symbols, and texts, are difficult to get a good result from reprojection or interpolation. Let's use the original projection to plot the map and investigate the result.

import matplotlib.pyplot as plt
import cartopy as ccrs
import cartopy.io.img_tiles as cimgt

tiles = cimgt.GoogleTiles()
image_crs = tiles.crs

fig, ax = plt.subplots(figsize=(16,12), subplot_kw=dict(projection=image_crs))

ax.set_extent([67, 75, 20, 26], crs=ccrs.crs.PlateCarree())

ax.add_image(cimgt.GoogleTiles(), 8)
plt.show()

The output plot: