Code/packages

RGoogleMaps package for R; for example, to make a map with arcs over the world.

GeoPlotLib for python.

Web Sites/services

MapBox, which was used to create this beautiful OpenStreetMap visualisation.

CartoDB, which is often used by the @TwitterData team, e.g. tweets during the oscars (below).

#Oscars2015 on Twitter. Relive the whole event with our animated map
LINK: http://t.co/fEVmLf28bZ pic.twitter.com/QnoK3sfqFJ

— Twitter Data (@TwitterData) February 23, 2015