如何在 R 中下载 GADM 数据？

Question

library(raster)   
france<-getData('GADM', country='FRA', level=1)

但是，该命令导致我出现此错误。

trying URL 'http://biogeo.ucdavis.edu/data/gadm2.8/rds/FRA_adm1.rds'
Error in utils::download.file(url = aurl, destfile = fn, method = "auto",  : 
  cannot open URL 'http://biogeo.ucdavis.edu/data/gadm2.8/rds/FRA_adm1.rds'

Answer 1

首先，从GADM 数据库下载所需的国家/地区数据，并将其保存到本地目录。确保您选择了R (SpatialPolygonsDataFrame)格式。法国有五个级别（从 0 级到 5 级）。您可以选择您需要的。

其次，读取.rds从 GADM with readRDS()function 下载的文件，并将其转换为data.framewith ggplot2::fortify().

library(ggplot2)
library(sp)
# assumed that you downloaded into a such path: '~/Downloads/FRA_adm1.rds':
path <- file.path(Sys.getenv("HOME"), "Downloads", "FRA_adm1.rds")
# FR map (Level 1) from GADM version 2.8
frRDS <- readRDS(path)
# Region names 1 in data frame
frRDS_df <- ggplot2::fortify(frRDS, region = "NAME_1")
head(frRDS_df)