R：创建一个世界网络地图

Question

我想在R中生成类似于the one below from this page的世界网络地图。

我一直在寻找一个允许我这样做的R包，但我找不到。有D3 JavaScript Network Graphs from R但我找不到世界网络地图示例 如何在R中创建类似的东西？

Answer 1

那么，FWIW：这是在地图上绘制顶点（“城市”）并使用箭头连接顶点之间边缘的一种快速和简单方法：

library(maps)
library(diagram)  
library(plotrix)
palette(rainbow(20))
data("world.cities")

pdf(tf <- tempfile(fileext = ".pdf"), width = 40, height = 20)

map('world', fill = TRUE, col = "lightgray", mar = rep(0, 4)) 

nodes <- transform(with(world.cities, world.cities[pop > 5e6,]), country.etc = as.factor(country.etc))
with(nodes, points(long, lat, col=country.etc, pch=19, cex=rescale(pop, c(1, 8)))) 

set.seed(1)
edges <- subset(data.frame(from = sample(nodes$name, 20, replace = TRUE), to = sample(nodes$name, 20, replace = TRUE), stringsAsFactors = F), from != to)
edges <- merge(merge(edges, nodes[, c("name", "long", "lat")], by.x = "from", by.y = "name"), nodes[, c("name", "long", "lat")], by.x = "to", by.y = "name")
edges$col <- as.integer(nodes$country.etc[match(edges$from, nodes$name)])

apply(edges[, -(1:2)], 1, function(x) curvedarrow(to=x[3:4], from=x[1:2], lcol=x[5], curve=.1, arr.pos = 1, lwd=.5))

dev.off()         
shell.exec(tf)

Answer 2

以下是使用geosphere和maps包的解决方案。 使用gcIntermediate函数，您可以“在用于定义大圆的两个点之间的大圆上的中间点。”

以下示例显示了JKF机场的航班同步情况（nycflights13包中的样本数据已过滤dplyr）：

library(maps)
library(geosphere)
library(dplyr)
library(nycflights13)


usairports <- filter(airports, lat < 48.5)
usairports <- filter(usairports, lon > -130)
usairports <- filter(usairports, faa!="JFK")
jfk <- filter(airports, faa=="JFK")

map("world", regions=c("usa"), fill=T, col="grey8", bg="grey15", ylim=c(21.0,50.0), xlim=c(-130.0,-65.0))


for (i in (1:dim(usairports)[1])) { 

inter <- gcIntermediate(c(jfk$lon[1], jfk$lat[1]), c(usairports$lon[i], usairports$lat[i]), n=200)

lines(inter, lwd=0.1, col="turquoise2")    
}

points(usairports$lon,usairports$lat, pch=3, cex=0.1, col="chocolate1")

这是基于我blog上发布的教程。