In chapter 6.6 of the book https://ggplot2-book.org/maps links to the osmar package are present. However, this package has been archived from R-Forge because
Package ‘osmar’ was removed from the CRAN repository.
Formerly available versions can be obtained from the archive.
Archived on 2022-06-20 as check problems were not corrected despite reminders.
A summary of the most recent check results can be obtained from the check results archive.
In chapter 6.6 of the book https://ggplot2-book.org/maps links to the osmar package are present. However, this package has been archived from R-Forge because