> library(maps)> library(geosphere)载入需要的程辑包：sp> map("state")#画美国地图> map("world")#画世界地图> xlim<-c(-171.738281,-56.601563)> ylim<-c(12.039321,71.856229)> map("world",col="#f2f2f2",fill=TRUE,bg="white",lwd=0.05,xlim=xlim,ylim=ylim)#通过设置坐标范围使焦点集中在美国周边，并且设置一些有关颜色
> #画一条弧线连线，表示社交关系> lat_ca<-39.164141> lon_ca<--121.64062> lat_me<-45.21300> lon_me<--68.906250> gcIntermediate(c(lon_ca,lat_ca),c(lon_me,lat_me),n=50,addStartEnd=TRUE) lon lat [1,] -121.64062 39.16414 [2,] -120.75830 39.50191 [3,] -119.86744 39.83294 [4,] -118.96805 40.15709 [5,] -118.06012 40.47422 [6,] -117.14367 40.78418 [7,] -116.21873 41.08682 [8,] -115.28534 41.38199 [9,] -114.34355 41.66956[10,] -113.39342 41.94937[11,] -112.43503 42.22127[12,] -111.46848 42.48513[13,] -110.49386 42.74080[14,] -109.51131 42.98815[15,] -108.52095 43.22701[16,] -107.52295 43.45727[17,] -106.51746 43.67879[18,] -105.50466 43.89143[19,] -104.48477 44.09506[20,] -103.45798 44.28955[21,] -102.42454 44.47479[22,] -101.38468 44.65065[23,] -100.33866 44.81702[24,] -99.28677 44.97379[25,] -98.22930 45.12084[26,] -97.16654 45.25810[27,] -96.09881 45.38544[28,] -95.02646 45.50280[29,] -93.94981 45.61008[30,] -92.86924 45.70722[31,] -91.78510 45.79413[32,] -90.69778 45.87075[33,] -89.60766 45.93704[34,] -88.51513 45.99294[35,] -87.42060 46.03841[36,] -86.32447 46.07342[37,] -85.22717 46.09793[38,] -84.12909 46.11194[39,] -83.03067 46.11543[40,] -81.93232 46.10840[41,] -80.83445 46.09085[42,] -79.73750 46.06280[43,] -78.64186 46.02427[44,] -77.54796 45.97529[45,] -76.45620 45.91589[46,] -75.36698 45.84611[47,] -74.28068 45.76602[48,] -73.19770 45.67566[49,] -72.11841 45.57510[50,] -71.04317 45.46442[51,] -69.97234 45.34369[52,] -68.90625 45.21300>> inter<-+ gcIntermediate(c(lon_ca,lat_ca),c(lon_me,lat_me),n=50,addStartEnd=TRUE)> lines(inter)> #转载数据> airports<-read.csv("http://datasets.flowingdata.com/tuts/maparcs/airports.csv",header=TRUE)> flights<-read.csv("http://datasets.flowingdata.com/tuts/maparcs/flights.csv",header=TRUE,as.is=TRUE)
> #实现多重联系> map("world",col="#f2f2f2",fill=TRUE,bg="white",lwd=0.05,xlim=xlim,ylim=ylim)> fsub<-flights[flights$airline=="AA",]> for(j in 1:length(fsub$airline)){+ air1<-airports[airports$iata==fsub[j,]$airport1,]+ air2<-airports[airports$iata==fsub[j,]$airport2,]+ inter<-gcIntermediate(c(air1[1,]$long,air1[1,]$lat),c(air2[1,]$long,air2[1,]$lat),n=100,addStartEnd=TRUE)+ lines(inter,col="black",lwd=0.8)+ }>
