请高手指教,以下代码都可以正常执行,为何生成的地图是下图白色地图,而不是彩色的中国地图?
install.packages("rgeos")
install.packages("mapdata")
library(rgeos)
library(sp)
library(maptools)
library(rgdal)
library(maps)
x<- readOGR ('d:/R/data/bou2_4p.shp')
getColor=function(mapdata,provname,provcol,othercol)
{
f=function(x,y) ifelse(x %in% y,which(y==x),0);
colIndex=sapply(mapdata@data$NAME,f,provname);
col=c(othercol,provcol)[colIndex+1];
return(col);
}
provname=c("北京市","天津市","河北省","山西省","内蒙古自治区",
"辽宁省","吉林省","黑龙江省","上海市","江苏省",
"浙江省","安徽省","福建省","江西省","山东省",
"河南省","湖北省","湖南省","广东省",
"广西壮族自治区","海南省","重庆市","四川省","贵州省",
"云南省","西藏自治区","陕西省","甘肃省","青海省",
"宁夏回族自治区","新疆维吾尔自治区","台湾省",
"香港特别行政区");
pop=c(1633,1115,6943,3393,2405,4298,2730,3824,1858,7625,
5060,6118,3581,4368,9367,9360,5699,6355,9449,
4768,845,2816,8127,3762,4514,284,3748,2617,
552,610,2095,200,693);
provcol=rgb(red=1-pop/max(pop)/2,green=1-pop/max(pop)/2,blue=0);
plot(x,col=getColor(x,provname,provcol,"white"),xlab="",ylab="");