第十一章 地图
download.file(url = "http://dapengde.com/r4rookies/us.csv",
destfile = "c:/r4r/us.csv")
us <- read.csv("c:/r4r/us.csv")
summary(us)
nlevels(us$state)
plot(us$lon, us$lat)
plot(us$lon, us$lat)
points(us$lon[us$state == "Texas"],
us$lat[us$state == "Texas"], col="blue")
cols <- rainbow(nlevels(us$state))
plot(us$lon, us$lat, col = cols[us$state], pch = 20)
lon.median <- tapply(us$lon, us$state, median)
lat.median <- tapply(us$lat, us$state, median)
text(labels = levels(us$state), x = lon.median, y = lat.median,
cex = 0.5, col = 'White')
points(-74.02, 40.73, pch = 17, cex = 2)
download.file(url = "http://dapengde.com/r4rookies/cm.zip",
destfile = "c:/r4r/cm.zip")
unzip(zipfile = "c:/r4r/cm.zip", exdir = "c:/r4r")
install.packages('rgdal')
require(rgdal)
cm <- readOGR(dsn = "c:/r4r/cm", layer = "bou2_4p")
plot(cm)
summary(cm)
is.factor(cm$NAME)
levels(cm$NAME) # 省市名称。
download.file(url =
"http://dapengde.com/r4rookies/aqi.csv",
destfile = "c:/r4r/aqi.csv")
aqi <- read.csv("c:/r4r/aqi.csv")
aqi
aqstandard <- c(0, 50, 100, 150, 200, 300, 500, Inf)
aqilevel <- cut(aqi$aqi[match(levels(cm$NAME),aqi$province)],
aqstandard)
mycol <- grey(seq(1, 0,
length.out = nlevels(aqilevel)))[aqilevel]
col <- cm$NAME
levels(col) <- mycol
plot(cm, col = as.character(factor(col)), axes = TRUE)
install.packages('plotrix')
library(plotrix)
legendn <- character((length(aqstandard) - 2) * 2 + 1)
legendn[seq(2, length(legendn), by = 2)] <-
aqstandard[2:(length(aqstandard)-1) ]
color.legend(
xl = 135, yb = 10, xr = 137, yt = 30,legend = legendn,
rect.col = grey(seq(1, 0, length.out = nlevels(aqilevel))),
align = "lb", gradient = "y") # 添加图例。
color.legend(
xl = 135, yb = 10, xr = 137, yt = 30,
legend = c('Excellent','Good','Lightly', 'Moderately',
'Heavily', 'Severely', 'OMG'),
rect.col = grey(seq(1, 0, length.out = nlevels(aqilevel))),
align = "rb", gradient = "y") # 添加图例。
install.packages('leafletCN')
require(leafletCN)
aqi$aqi[aqi$aqi == -1] <- NA
pvs <- regionNames("china")
loc <- match(pvs, aqi$province)
aqi2 <- data.frame(name = pvs, value = aqi$aqi[loc])
geojsonMap(dat = aqi2, mapName = "china",
popup = paste(aqi2$name, aqi2$value),
legendTitle = "AQI")