To avoid downloading the same maps again and again, ggmap uses a "file drawer" to store the maps you've downloaded. By default, they will be stored in a session specific temporary directory which will be deleted each time you quit R. If you want them to persist across sessions, set the global option "ggmap.file_drawer".
file_drawer(...)
Examples
## Not run:if server is unresponsive, R check will fail
file_drawer()dir(file_drawer())# The first time you run this, the tiles are downloaded from the servermap <- get_stadiamap()# The second time, the local cache is used so it's much fastermap <- get_stadiamap()dir(file_drawer())## End(Not run)