How To Upload Shapefile Into R

If yous did not discover the geospatial information you lot demand in existing R packages (encounter the map section), you need to find this data 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 go along together in the aforementioned folder.

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

Discover and download a shapefile.

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

You tin can download it and unzip it with R:

Read it with `rgdal`

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

As a effect you become 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:

summary(my_spdf): tells y'all the max and min coordinates, the kind of projection in use
length(my_spdf): how many regions you lot have
head(my_spdf@data): the firs few rows of the data slot associated with the regions

Plot information technology with `base R`

The basic plot() function knows how to plot a geospatial object. Thus yous simply need to laissez passer information technology my_spdf and add a couple of options to customize the output.

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 exist transformed using the tidy() function of the broom package. The region argument of this function wait 1 of the column name if the @data slot. It will exist the region name in the new dataframe.

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