CODEWITHSUNDEEP
rggplot2geospatialshapefile
zappbran
zappbran

Reputation: 145

Shapefile being read incorrectly while trying to plot spatial object?

I'm new to geo spatial analysis, and am having trouble reading my SHP file correctly when trying to do overlay plots with ggplot2.

For example, if I use the .shp file from http://thematicmapping.org/downloads/TM_WORLD_BORDERS_SIMPL-0.3.zip

And read my data using readOGR() from the rgdal package

shape_x <- readOGR("TM_WORLD_BORDERS_SIMPL-0.3.shp")

I can draw the following using base R

plot(shape_x)

enter image description here

But when I try using ggplot, I get something funky:

ggplot() +
geom_polygon(data=as.data.frame(shape_x), aes(shape_x$LON, shape_x$LAT),
             fill="white", colour="black")

enter image description here

I'm sure I'm missing something simple, I'm not sure how to specify the correct xy coordinates in aes() in geom_polygon()

Thank you in advance!

Upvotes: 2

Views: 59

Answers (1)

TarJae
TarJae

Reputation: 78927

Here is another approach using the sf package:

library(sf)
shape_x <- st_read("TM_WORLD_BORDERS_SIMPL-0.3.shp")

ggplot() +
  geom_sf(data = shape_x)

enter image description here In case you insist to do it with rgdal then we have to bring the shape data in a certain form so that ggplot can read it: (we use broom::tidy for this):

library(rgdal)
library(ggplot2)
library(broom)

url <- "http://thematicmapping.org/downloads/TM_WORLD_BORDERS_SIMPL-0.3.zip"
destfile <- "TM_WORLD_BORDERS_SIMPL-0.3.zip"
download.file(url, destfile)
unzip(destfile)
shape_x <- readOGR("TM_WORLD_BORDERS_SIMPL-0.3.shp")
shape_x_df <- tidy(shape_x)
ggplot() +
  geom_polygon(data = shape_x_df, 
               aes(x = long, y = lat, group = group), 
               fill = "white", color = "black")

enter image description here

Upvotes: 1

Related Questions