CODEWITHSUNDEEP
rzoomingshapefileggmap
alex
alex

Reputation: 103

How can I zoom in a ggmap plot that uses shapefiles?

I’m trying to plot a map of Europe with every country filled in a colour according to a certain numeric value – I thought this should be no problem with shapefiles (that I got here http://www.naturalearthdata.com/downloads/10m-cultural-vectors/) and ggmap. However it only works for a very large map but I am not able to properly zoom in.

I tried to do so by setting xlim() and ylim(), but since thereby I was cutting off shapes at the edges, R connected points that were not supposed to be connected. For ggplot I could solve this issue by using coord_fixed(xlim, ylim) instead, but when applying the same to my ggmap-plot the country shapes and the map would not fit onto each other anymore.

ggmap with wrong shapes

Here is my code that I used for the plot:

my.map <- get_map(location = "europe", source = "google", maptype = "satellite", zoom = 3)

ggmap(my.map) + 
  geom_polygon(aes(x = long, y = lat, group = group), fill = eu$value, size = .2, color = 'green', data = eu, alpha = 0.5) +
  coord_fixed(xlim = c(0, 35),  ylim = c(35, 65), ratio = 1.6)

Does anybody know how I can solve this problem?
(I know it works with ggplot but I'd really like to use ggmap.)

Thank you!

Upvotes: 1

Views: 2056

Answers (1)

chrki
chrki

Reputation: 6333

Use coord_map() instead of coord_fixed():

my.map <- get_map(location = "europe", source = "google", maptype = "satellite", zoom = 3)
ggmap(my.map)+
  geom_polygon(aes(x=long, y = lat, group = group), fill='white', size=.2, color='green', data=eu, alpha=0.5)+
  coord_map(xlim=c(0, 35), ylim=c(35, 65))

resulting map

Upvotes: 2

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