I'm trying to draw a world map using `ggplot`. My code is in my [gist file](https://gist.github.com/pachevalier/38666a7fecab76f986b4). 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()

```

![map with <code>coord_map</code>](https://i.stack.imgur.com/hxCHH.png)

```
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()

```

![enter image description here](https://i.stack.imgur.com/Tllu1.png)

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()

```

![enter image description here](https://i.stack.imgur.com/06Jkq.png)

Does anyone has an answer ?