It appears that {revgeo} has been taken off CRAN, therefore the instructions install.packages("revgeo") no longer works.
This was the message from CRAN:
Package ‘revgeo’ was removed from the CRAN repository.
Formerly available versions can be obtained from the [archive](https://cran.r-project.org/src/contrib/Archive/revgeo).
Archived on 2025-03-24 as email to the maintainer is undeliverable.
A summary of the most recent check results can be obtained from the [check results archive](https://cran-archive.r-project.org/web/checks/2025/2025-03-24_check_results_revgeo.html).
Please use the canonical form https://cran.r-project.org/package=revgeo to link to this page.
It appears that {revgeo} has been taken off CRAN, therefore the instructions
install.packages("revgeo")no longer works.This was the message from CRAN: