Revision as of 00:09, 29 March 2021 by A.heerdegen (talk | contribs) (Changed last graphic, added link to code)

Background images for cartopy plots

Cartopy is a python package for geospatial data processing that can be used to produce production quality maps. It is the supported package for this purpose and is part of our python conda distribution installed at NCI.

The cartopy package has replaced the now deprecated basemap. One of the useful functions provided by basemap that has no equivalent in the cartopy package is the ability to easily add a background "NASA Blue Marble" image.

We have downloaded three NASA blue marble products (bluemarble, city lightsexplorer base map) and made them easily available to use as a background for a cartopy plot. The shut up and show me how is:

ax = plt.subplot(111, projection=ccrs.PlateCarree()) 
ax.background_img(name='bluemarble', resolution='high')

replace bluemarble with lights or explorer to access the different products. All are avaible in four different resolutions: low, medium, high and extrahigh (aliases for 1.0deg, 0.5deg, 0.25deg and 0.1deg).

Examples of each plot

Blue Marble:

NASA Blue Marble as cartopy background

City Lights:

NASA City Lights background plot with cartopy

Explorer Base Map:

NASA Explorer Base Map as cartopy background

Blue Marble as a background image with SST data in a near side cartopy projection

Blue Marble background image with SST data plotted in near side cartopy projection

The code to generate the picture above is available as an jupyter notebook.