俄罗斯的阴谋一分为二

Question

我正在尝试从 shp 文件中绘制俄罗斯，但俄罗斯总是分成两部分出现。我如何让俄罗斯重新团结起来？

我尝试了几个 shp 文件，例如 http://www.naturalearthdata.com/downloads/10m-cultural-vectors/ Admin 1 – 州、省；下载无大湖 (14.11 MB) 版本 3.0.0

 shp <- readOGR("ne_10m_admin_1_states_provinces_lakes.shp")

子集到俄罗斯

names(shp)
rus <- shp[shp$admin == "Russia" , ]

x11()
plot(rus)

Answer 1

既然要画图，可以将shapefile强化为data frame，修改-180区域的经度坐标，将结果画在ggplot:

library(rgdal); library(ggplot2)

# read in the shapefile & subset to Russia
shp <- readOGR(dsn = "ne_10m", layer = "ne_10m_admin_1_states_provinces_lakes")
rus <- shp[shp$admin == "Russia", ]

# fortify to data frame & modify longitude coordinates in the -180 region.
rus.fortify <- fortify(rus) %>%
  mutate(long = ifelse(long < -100, long + 180*2, long))

# plot to verify
ggplot(rus.fortify,
       aes(x = long, y = lat, group = group)) +
  geom_polygon(fill = "white", col = "black") +
  coord_map() #default projection is mercator

我刚刚还从了解到您可以指定不同的投影系统。鉴于俄罗斯有多大，这应该是相关的：

ggplot(rus.fortify,
       aes(x = long, y = lat, group = group)) +
  geom_polygon(fill = "white", col = "black") +
  coord_map("azequalarea")

俄罗斯的阴谋一分为二

Plot of Russia split in two

plot

r

shapefile