In performing network analysis, I want to plot network graph on maps. Ggmap seems the first choice, but it require API access.
Is there any free and equivalent/alternative (to ggmap) options that don’t require API access?
Thank you.
Open Street Map should suit your needs. Here is a package for it: https://cran.r-project.org/web/packages/OpenStreetMap/index.html. More information: https://wiki.openstreetmap.org/wiki/OSM_Scientific_Tools