In my previous post, I discussed how to use OpenStreetMaps (and standard plotting functions of R) to visualize John Snow’s dataset. But it is also possible to use Google Maps (and ggplot2 types of graphs). library(ggmap) get_london <- get_map(c(-.137,51.513), zoom=17) london <- ggmap(get_london) Again, the tricky part comes from the fact that the coordinate representation system, here, is not...