gadMaps - GeoJson generator and plotter out of the map data from http://gadm.org/
The package allows user to get as geojson and plot precise countries map from http://gadm.org/. Each map has different details levels from 0 (only external country's borders) to 4, or 5 (internar borders, e.g. redions, provinces etc.); depending on the country, highest level can be less than 4.
To install the latest version of the package from gitHub, use the following command in R console:
devtools::install_github("kislerdm/gadMaps")if you don't have the package devtools, install it by executing
install.package("devtools")