Background map in R

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R is an great tool for geospatial data analysis. Heaps of dedicated packages exist. Building a map follows those 2 steps:

Find data, load it in R: region boundaries can be stored in shapefiles or geoJSON files. Some R libraries also provide the data for the most common places. It is also possible to use google map style backgrounds.

Manipulate and plot it: once geo data are loaded in R you get a geospatial object that has specific features. You can manipulate it and plot it with packages like sp or ggplot2

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The leaflet R package is a wrapper of the Javascript leaflet.js library. It allows to build stunning interactive maps in minutes with R. Maps can be exported and standalong html files, or be embeded in a R markdown file or a shiny application.

Leaflet maps are interactive: try to zoom and drag.

See Code

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The ggmap library makes it easy to retrieve raster map tiles from popular online mapping services like Google Maps, OpenStreetMap or Stamen Maps, and plot them using the ggplot2 framework. It produces static maps like these. Click on an image to get the related code snippet.

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A few libraries provide the most common spatial objects. It avoids the struggle to find the information somewhere on the web. Maps library: Canada, France, Italy, USA and its regions, world cities, NZ. Mapdata library (China, Japan, NZ, World in High resolution) and the oz library (Australia).

See all countries

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If you are not satisfied with the previous options, you can search the web to find the spatial object you need. This information will most likely be stored under on of those 2 formats:

• shape file: can be read with the rgdal package as described here.
• geojson file: can be read with geojsonio as explained here.

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Once you've got your geospatial data loaded into R, you are ready to manipulate it. Examples below show how to select a region, how to simplfy the boundaries to get a lighter object, how to compute the region centroids and more.