Why does coord_map produce a weird output?

Question

I'm trying to draw a world map using `ggplot`. My code is in my gist file. The output is correct when I don't use `coord_map` but very strange when I use `coord_map` : ``` ggplot(data = test, aes(fill = x)) + geom_map(aes(map_id = id), map =world.ggmap, color = "white") + expand_limits(x = world.ggmap$long, y = world.ggmap$lat) + theme_tufte() + coord_map() ``` ``` ggplot(data = test, aes(fill = x)) + geom_map(aes(map_id = id), map =world.ggmap, color = "white") + expand_limits(x = world.ggmap$long, y = world.ggmap$lat) + theme_tufte() ``` I've got the same error when I use data from the maps package : ``` library(ggplot2) library(maps) world <- map_data("world") ggplot() + geom_map( data=world, aes(x=long, y=lat, group = group, map_id = region),colour="white", fill="grey10", map = world ) + coord_map() ``` Does anyone has an answer ?

Accepted Answer

I had a similar problem before, due to longitude values outside the range [-180,180]. In your example the data do not have this problem but my trick seems to work also here. In my case I just used 'xlim' to exclude the problematic data.

This solution seems to work in your case also (I used the code from your gist):

```
map+coord_map(xlim=c(-180,180))
```

It produces the following map:

There is still a problem with Antarctica, you can also consider clipping it too if you don't need this area:

```
map+coord_map(xlim=c(-180,180), ylim=c(-60, 90))
```

Why does coord_map produce a weird output?

Solution

Problem