How I use shapefiles in R with ggplot2 and RGDAL

shapefile.r

library(rgdal)     # R wrapper around GDAL/OGR
library(ggplot2)   # for general plotting
library(ggmaps)    # for fortifying shapefiles

# First read in the shapefile, using the path to the shapefile and the shapefile name minus the
# extension as arguments
shapefile <- readOGR("path/to/shapefile/", "name_of_shapefile")

# Next the shapefile has to be converted to a dataframe for use in ggplot2
shapefile_df <- fortify(shapefile)

# Now the shapefile can be plotted as either a geom_path or a geom_polygon.
# Paths handle clipping better. Polygons can be filled.
# You need the aesthetics long, lat, and group.
map <- ggplot() +
geom_path(data = shapefile_df, 
          aes(x = long, y = lat, group = group),
          color = 'gray', fill = 'white', size = .2)

print(map) 

# Using the ggplot2 function coord_map will make things look better and it will also let you change
# the projection. But sometimes with large shapefiles it makes everything blow up.
map_projected <- map +
  coord_map()
  
print(map_projected)

Thanks for the fortify tip!

Thanks for this. Was really helpful. I think line 3 should import ggmap not ggmaps though :)

Thanks for this. I might be wrong, but if I recall well, the library's name is ggmap, and not ggmaps. Cheers!

Thank u so much, it is very helpful!

Thanks fo much!

Just a quick question, it says Ignoring unknown parameters: fill for geom_path(). How can I fix it please?

If you didn't work it out, Xiaohk, the fill parameter only work for geom_polygon.

fortify did the trick!

Thanks!

Thanks. Fortify did the trick for me

I think "ggmaps" is now "ggmap"

It seems as if broom::tidy() is becoming the preferred method of converting shapefiles to dataframes.

The function description has changed to:

Rather than using this function, I now recommend using the broom package, which implements a much wider range of methods. fortify may be deprecated in the future.

is it possible to read from github directly? ie i have r script and shapefile/geodatabase all on github, how can i connect them?

Hi. when using the converted shapefile the map appears distorted, how can I solve it?
They know how to color each province according to the prevalence of something, with plot me it was much easier. Thank you

Thanks a lot! fortify is the best