The matplotlib basemap toolkit is a library for plotting 2D data on maps in Python. It is similar in functionality to the matlab mapping toolbox, the IDL mapping facilities, GrADS, or the Generic Mapping Tools. PyNGL and CDAT are other libraries that provide similar capabilities in Python.

Basemap does not do any plotting on it’s own, but provides the facilities to transform coordinates to one of 25 different map projections (using the PROJ.4 C library). Matplotlib is then used to plot contours, images, vectors, lines or points in the transformed coordinates. Shoreline, river and political boundary datasets (from Generic Mapping Tools) are provided, along with methods for plotting them. The GEOS library is used internally to clip the coastline and polticial boundary features to the desired map projection region.

Basemap is geared toward the needs of earth scientists, particularly oceanographers and meteorologists. Jeff Whitaker originally wrote Basemap to help in his research (climate and weather forecasting), since at the time CDAT was the only other tool in python for plotting data on map projections. Over the years, the capabilities of Basemap have evolved as scientists in other disciplines (such as biology, geology and geophysics) requested and contributed new features.

Cartopy, New Management, and EoL Announcement

Starting in 2016, Basemap came under new management. The Cartopy project will replace Basemap, but it hasn’t yet implemented all of Basemap’s features. All new software development should try to use Cartopy whenever possible, and existing software should start the process of switching over to use Cartopy. All maintenance and development efforts should be focused on Cartopy.

Ben Root has volunteered to take over maintenance of Basemap until 2020. Pull requests will be reviewed, and regressions will be fixed. Also, this maintenance will ensure compatibility with packages like NumPy and Matplotlib. New features will be accepted, but we stress that new development efforts should be focused on Cartopy. When Python 2.7 is officially EoL’ed in 2020, a release of Basemap will be made and support from Ben Root will end.