不同的坐标轴转换绘制世界地图

1需要构建一个excel表，存储了世界各国人口数

population.csv

2数据和颜色数据准备

library(maps)

library(ggplot2)

library(RColorBrewer)

color1<-brewer.pal(9,"YlOrRd")[c(3,4,5,6,7,8,9)]

color2<-brewer.pal(9,"Greens")[c(4,6)]

color(<-crev(color2),color1)

p<-file.choose()

mydata<-read.csv(p,stringsAsFactors=FALSE) #这里读取的就是我们上面的population.csv

names(mydata)[1]<-c("Country" ,"Scale" ,"million","fan" ) #重新定义列明，并在原基础上新加了million和fan列

mydata$million<-mydata$Scale/1000000

mydata$fan<-cut(mydata$million,

breaks=c(min(mydata$million,na.rm=TRUE),

0,300,600,900,1200,1500,1800,2100,2400,

max(mydata$million,na.rm=TRUE)),

labels=c(" <=0","0~300","300~600","600~900","900~1200","1200~1500",

"1500~1800","1800~2100","2100~2400"," >=2400"),

order=TRUE)

world_map <- map_data("world") #读取R maps自带的包文件world，这样我们就可以直接绘制地图了

3绘制mercator坐标轴转换地图

-mercator--------------------------------------

ggplot()+

geom_map(data=mydata,aes(map_id=Country,fill=fan),map=world_map)+

geom_path(data=world_map,aes(x=long,y=lat,group=group),colour="black",size=.2)+

coord_map("mercator",xlim=c(-180,180), ylim=c(-90, 90))+

scale_y_continuous(breaks=(-3:3)*30) +

scale_x_continuous(breaks=(-6:6)*30) +

scale_fill_manual(name="million dollars",values=color,na.value="grey75")+

guides(fill=guide_legend(reverse=TRUE)) +

theme_minimal()+

theme(

text=element_text(size=15)#

)

mercator

4使用albers坐标系转换

ggplot()+

geom_map(data=mydata,aes(map_id=Country,fill=fan),map=world_map)+

geom_path(data=world_map,aes(x=long,y=lat,group=group),colour="black",size=.2)+

coord_map("albers", parameters = c(0, 0))+

scale_y_continuous(breaks=(-3:3)*30) +

scale_fill_manual(name="million($)",values=color,na.value="grey80")+

guides(fill=guide_legend(reverse=TRUE))+

theme_minimal()+

theme(axis.text.x=element_blank())

albers