R中的Cartogram + choropleth地图

Posted 2023-01-08

我最近一直在使用ggplot2来创建一堆等值线。我想知道是否可以使用ggplot2来创建类似于此的地图（来自WorldMapper）：

这是一个等角度，其中shapefile多边形被扭曲以表示相对人口数量。我相信这被称为制图。他们用一堆其他变量做到这一点。在Choropleth R Challenge的精神，有谁知道如何使用R？

答案

可以在CRAN上找到的cartogram package具有您想要的橡胶板扭曲式制图。

另一答案

这可能有效：

您需要预安装FFTW。 Rcartogram and getcartr you will need devtools。

不知道如何在ggplot2中这样做，但这是另一种选择。

这里我使用Thematic World Map的shapefile，下载并解压后，你会得到一个名为TM_WORLD_BORDERS-0.3的文件夹。

对于等值线/制图，您将首先使用大小重新整形，并使用特征进行着色：

library(rgdal)#needed for readOGR
library(sp) #needed for spplot
library(Rcartogram)
library(getcartr)
setwd("<your_directory_with_shapefile>") #to the file that has your shapefile and your information file (in this case, a csv named datR)
#read shapefile
#here i have a folder with a shapefile and a csv with columns as ISO (IS02 for convenience) country and value
worldR <- readOGR(dsn = getwd(), layer= "TM_WORLD_BORDERS-0.3") # If reading a shapefile, the data source name (dsn= argument) is the folder (directory) where the shapefile is, and the layer is the name of the shapefile (without the .shp extension)
#names(worldR) #note how here there are columns for ISO2 (which matches a column named 'iso' in datR and LAT\LON
#[1] "FIPS"      "ISO2"      "ISO3"      "UN"        "NAME"      "AREA"      "POP2005"   "REGION"    "SUBREGION" "LON"       "LAT"
proj4string(worldR)
datR <- read.csv("datR.csv") #this is a file that has one column called 'score' and one column called size':

   head(datR)
  #  iso size     score
  #1  AE  323 0.9819077
  #2  AR  262 0.9591067
  #3  AT 7481 0.9987313
  #4  AU 5425 0.9837414
  #5  BA   31 0.9871938
  #6  BB   99 0.9715991

  ##Merge SpatialPolygonsDataFrame with other info
  map_dat <- merge(worldR, datR, by.x="ISO2",by.y="iso")
  #remove coordinate reference system arguments
  proj4string(map_dat) <- CRS(as.character(NA)) # from here https://github.com/chrisbrunsdon/getcartr/issues/1
  world.carto <- quick.carto(map_dat, map_dat$size, blur = 0)
  #plot(world.carto) #cartogram without anything
  #spplot size, color
  my.palette = c("#ff0000", "#ff8000", "#ffff00", "#bfff00","#00ff00") #red, orange, yellow, light green, dark green
  spplot(world.carto, 'score', col.regions = my.palette, cuts = length(my.palette)-1,main="Choropleth of score and cartogram of size")

这应该给你一个类似于这个的情节：

我急忙这样做，让我知道它是否有效