[英]How to convert state name to latitude and longitude to create choropleth with ggvis in R?
我想使用ggvis軟件包為每個州的收入值創建一個Choropleth。 以下是我的數據。 我認為映射數據需要緯度和經度列。 有人知道如何將州名稱轉換為緯度和經度嗎? 非常感謝!
mapdata<-data.frame(
state=c("alabama","alaska","arizona","arkansas","california","colorado","connecticut","delaware","florida","georgia","hawaii","idaho","illinois","indiana","iowa","kansas","kentucky","louisiana","maine","maryland","massachusetts","michigan", "minnesota","mississippi","missouri","montana","nebraska","nevada","new hampshire","new jersey","new mexico","new york","north carolina","north dakota","ohio","oklahoma", "oregon","pennsylvania","rhode island","south carolina","south dakota","tennessee","texas","utah","vermont","virginia","washington","west virginia","wisconsin","wyoming"),
income=runif(50,min=100,max=9000))
這是一種方法。 我使用的是ggplot
而不是ggVis
但這應該可以幫助您入門。
library(raster) # for getData(...)
library(ggplot2)
library(data.table)
usa <- getData('GADM',country='USA',level=1) # shapefile of US states
shp <- usa[(!usa$NAME_1 %in% c("Alaska","Hawaii")),] # remove AK, HI for this example
gg.dt <- setDT(fortify(shp)) # convert shapefile to format ggplot can use
# merge with attribute table
gg.dt <- gg.dt[setDT(cbind(id=rownames(shp@data),shp@data)),on="id"]
gg.dt[,state:=tolower(NAME_1)] # convert state names to lower case
gg.dt <- gg.dt[setDT(mapdata),on="state"] # merge with mapdata
ggplot(gg.dt, aes(x=long, y=lat, group=group,fill=revenue)) +
geom_polygon(color="grey50", size=0.1)+
scale_fill_gradientn(colours=rev(heat.colors(10)))+
coord_map()
因此,這里有一個ggvis
解決方案(可能應該是一個單獨的答案,但是是WTH)。 事實證明,上面的shapefile具有很高的分辨率,而ggvis
不能處理那么大的文件。 因此,這里我們下載了一個具有美國狀態邊界的低分辨率shapefile,使用data.frames進行合並(與低分辨率shapefile足夠快),然后使用ggvis
進行渲染。
library(rgdal) # for readOGR(...)
library(ggplot2) # for fortify(...)
library(ggvis)
# load low resolution US state shapefile (1:20MM)
url <- "http://www2.census.gov/geo/tiger/GENZ2014/shp/cb_2014_us_state_20m.zip"
tf <- tempfile()
td <- tempdir()
download.file(url,tf, mode="wb") # download shapefile archive of US state boundaries
unzip(tf, exdir=td) # unzip into directory td
usa <- readOGR(dsn=td, layer="cb_2014_us_state_20m")
shp <- usa[(!usa$STUSPS %in% c("AK","HI")),] # remove AK, HI for this example
gg.df <- fortify(shp) # convert shapefile to format ggvis can use
gg.df <- merge(gg.df,cbind(id=rownames(shp@data),shp@data),by="id") # merge with attribute table
gg.df$state <- tolower(gg.df$NAME) # convert state names to lower case
gg.df <- merge(gg.df,mapdata,by="state") # merge with mapdata
gg.df <- gg.df[order(gg.df$order),] # reset to original order
gg.df %>%
group_by(group) %>%
ggvis(~long, ~lat) %>%
layer_paths(fill= ~revenue)
有一個關於創建等值線圖使用一個體面的博客文章ggvis
這里 。 如果您想要自定義顏色(如先前的答案所示),請參閱文章。
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