R显示形状文件不正确

Question

我尝试从this site的R中打开形状文件

shape        <- readOGR(dsn = "/home/user/QGis/50m_physical", layer = "ne_50m_land")
shape_bord   <- readOGR(dsn = "/home/user/QGis/50m_cultural", layer = "ne_50m_admin_0_boundary_lines_land")

map<- ggplot()+
geom_polygon(data = shape, aes(x = long, y = lat, group = group), colour = "black", fill = NA)+
geom_polygon(data = shape_bord, aes(x = long, y = lat, group = group), colour = "green", fill = NA)

某些文件的管理边界为双行。

我该如何解决这个问题？

https://www.naturalearthdata.com/http//www.naturalearthdata.com/download/50m/cultural/ne_50m_admin_0_boundary_lines_land.zip