Making simple maps - 1854 London Streets

 Plotting an entire country, district, lakes and forests can be seen as a task for polygons while plotting streets, roads, and rivers a quest for paths to handle. Really informative maps would request much more than this recipe is going to teach but we're getting there. This recipe is going to show you how to plot some 1854 London streets.

Do not get anxious, maps are pretty cool and there is plenty of stuff to learn. Step by step, this chapter will introduce you to a lot of useful ones. This recipe's intention is to show you how maps can simply be translated into paths (and polygons); later, we will be improving this very map to get a result very similar to the one that John Snow (the doctor, not the ranger) breed.

Getting ready

Besides the regulars (ggplot2, ggvis, and plotly), the king (the king being this recipe) demands the HistData package:

> if( !require(HistData)){ install.packages('HistData')}

For now, we're still relying on packages to bring...