利用R语言画出两地路线图

发一篇教大家如何用R语言画路线图的攻略~

~\(≧▽≦)/~

题目是这样的：

利用R的地图包，提取武汉地图，并在图上标注一条从华中师范大学北门到黄鹤楼的路线.

首先，读取需要用到的R包~

library(maptools)
library(sp)
library(ggplot2)
library(mapproj)

再然后，在国家基础地理信息中心上下载地级市的shp地图包~这个网站我当时试了好多次还是登不上去，又从网上找了一个数据包~

当然你找百度地图，谷歌地图神马的，只要能拿到市级地图都行~R语言自带的包没有精确到市级。。。

 http://pan.baidu.com/s/1hs03gUg（如果分享过期了可以上网搜索BOUNT_poly.shp）

读入地级市包里的这个文件

mydat = readShapePoly("d:/rstudy/BOUNT_poly.shp")

按照99年制定的名字标准找到武汉市

tmp = iconv(mydat$NAME99, from = "GBK")
grep("武汉", tmp, value = TRUE)

显示武汉市对应ADCODE99编码

mydat$ADCODE99[grep("武汉", tmp)]

接下来就是把地图数据从地图包里找出来啦~稍微改一下名称~

Wuhan = mydat[substr(as.character(mydat$ADCODE99), 1, 4) == "4201",]
mysh = fortify(Wuhan)
mysh = transform(mysh, id = iconv(id, from = 'GBK'), group = iconv(group, from = 'GBK'))
head(mysh, n = 2)
names(mysh)[1:2] = c("x","y")   

为了好看，要涂上漂亮哒颜色~不过作为一个重度选择困难症，还是用随机数涂颜色啦~

（其实是因为网上的教程里有现成的随机数涂色╮(╯▽╰)╭）

先弄一串随机数把~

myepidat = data.frame(id = unique(sort(mysh$id)))
myepidat$rand = runif(length(myepidat$id))
myepidat

E <- c(114.31,114.37)
N <- c(30.55,30.52)
place <- c('黄鹤楼','华师')
data <- data.frame(E,place,N)

最后画出地图，涂色，标出目标点，连线。（可能是游戏打多了，用的红到绿的渐变色，地点用的是黄色，连线用蓝色~不要嘲笑我哒审美，我可是试了好多颜色哒~）

╮(╯▽╰)╭

csmap = ggplot(myepidat) +geom_map(aes(map_id = id, fill = rand), color = "white", map = mysh) +scale_fill_gradient(high = "red",low = "darkgreen") +geom_point(aes(E, N),data = data,colour="yellow") +geom_line(aes(E, N),data = data, colour = "blue",size = 1.5)+geom_text(data = data,aes(E, N, label = place),hjust = 1.2,size = 3) +expand_limits(mysh) + coord_map()
print(csmap)

 

全部代码：

library(maptools)
library(sp)
library(ggplot2)
library(mapproj)mydat = readShapePoly("d:/rstudy/BOUNT_poly.shp")
tmp = iconv(mydat$NAME99, from = "GBK")
grep("武汉", tmp, value = TRUE)
grep("武汉", tmp)
mydat$ADCODE99[grep("武汉", tmp)]
Wuhan = mydat[substr(as.character(mydat$ADCODE99), 1, 4) == "4201",]
mysh = fortify(Wuhan)
mysh = transform(mysh, id = iconv(id, from = 'GBK'), group = iconv(group, from = 'GBK'))
head(mysh, n = 2)
names(mysh)[1:2] = c("x","y")   
myepidat = data.frame(id = unique(sort(mysh$id)))
myepidat$rand = runif(length(myepidat$id))
myepidat
E <- c(114.31,114.37)
N <- c(30.55,30.52)
place <- c('黄鹤楼','华师')
data <- data.frame(E,place,N)
csmap = ggplot(myepidat) +geom_map(aes(map_id = id, fill = rand), color = "white", map = mysh) +scale_fill_gradient(high = "red",low = "darkgreen") +geom_point(aes(E, N),data = data,colour="yellow") +geom_line(aes(E, N),data = data, colour = "blue",size = 1.5)+geom_text(data = data,aes(E, N, label = place),hjust = 1.2,size = 3) +expand_limits(mysh) + coord_map()
print(csmap)

运行结果：