R：创建世界网络图

Question

我想生成一个类似于the one below from this page的R世界网络图。

我一直在寻找的R包，让我这样做，但我一直没能找到一个。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

好，FWIW：这里有一个快速的&肮脏的方式在地图上绘制的顶点（“城市”）和连接顶点之间的边缘与箭头：

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

这里是一个解决方案使用geosphere和maps包。 使用gcIntermediate函数可以“在用于定义大圆的两点之间的大圆上的中间点”。

这里是示出从JKF机场航班conncetions（样本数据从nycflights13封装dplyr过滤）的示例：

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") 

这是基于贴在一个教程我的blog。