Open and Plot Shapefiles in R

Shapefiles are a common way to store geospatial data. This post explains how to read it with R and the rgdal package, and how to plot it in base R or with ggplot2.

Background map section About Maps

If you did not find the geospatial data you need in existing R packages (see the map section), you need to find this information elsewhere on the web.

Usually, you will find it as a shape file format. This format is composed by several files that you need to keep together in the same folder.

Note: if you found a .geoJSON file, read this post instead.

Find and download a shapefile.

You need to dig the internet to find the shape file you are interested in. For instance, this URL will redirect you to a zipped shape file containing the worl boundaries.

You can download it and unzip it with R:

# Download the shapefile. (note that I store it in a folder called DATA. You have to change that if needed.)
download.file("" , destfile="DATA/")
# You now have it in your current working directory, have a look!

# Unzip this file. You can do it with R (as below), or clicking on the object you downloaded.
system("unzip DATA/")
#  -- > You now have 4 files. One of these files is a .shp file! (TM_WORLD_BORDERS_SIMPL-0.3.shp)

Read it with rgdal

The rgdal package offers the readOGR() function that allows to read shapefile using the following syntax.

As a result you get a geospatial object (my_spdf here) that contains all the information we need for further mapping. Please try th following command to understand how this object works:

# Read this shape file with the rgdal library. 
my_spdf <- readOGR( 
  dsn= paste0(getwd(),"/DATA/world_shape_file/") , 

# -- > Now you have a Spdf object (spatial polygon data frame). You can start doing maps!

Plot it with base R

The basic plot() function knows how to plot a geospatial object. Thus you just need to pass it my_spdf and add a couple of options to customize the output.

# Basic plot of this shape file:
plot(my_spdf, col="#f2f2f2", bg="skyblue", lwd=0.25, border=0 )

Plot it with ggplot2

It is totally possible (and advised imo) to build the map with ggplot2. However, ggplot2 takes as input data frames, not geospatial data.

my_spdf thus needs to be transformed using the tidy() function of the broom package. The region argument of this function expect one of the column name if the @data slot. It will be the region name in the new dataframe.

Once the data frame is created, it is plotted using the geom_polygon() function as described below.

# 'fortify' the data to get a dataframe format required by ggplot2
spdf_fortified <- tidy(my_spdf, region = "NAME")

# Plot it
ggplot() +
  geom_polygon(data = spdf_fortified, aes( x = long, y = lat, group = group), fill="#69b3a2", color="white") +

Related chart types

Hexbin map
Bubble map


This document is a work by Yan Holtz. Any feedback is highly encouraged. You can fill an issue on Github, drop me a message on Twitter, or send an email pasting with

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