So back in 2013 I posted a little function I wrote for grabbing all the relevant files that make up a shapefile from a URL. Turns out it doesn’t play so well with Windows 7 or Windows 8 (HT: John Lewis). Below is a reprised version that at least works on Ubuntu 14.04 and Windows 7. Haven’t tested it beyond that and supressing the warnings to get httr::GET to not complain too much about FTP seems a bit unclean. Well, you get what you pay for.

For all this to run you’ll need RCurl, httr, sp, and rgdal.

download_shp<-function (shape_url, layer, outfolder = ".") 
{
  if (length(grep("/$", shape_url)) == 0) {
    shape_url <- paste(shape_url, "/", sep = "")
  }
  
  shapefile_ext <- c(".shp", ".shx", ".dbf", ".prj", ".sbn", 
                     ".sbx", ".shp.xml", ".fbn", ".fbx", ".ain", ".aih", ".ixs", 
                     ".mxs", ".atx", ".cpg")

  xlogic <- NULL
  if(substr(shape_url,1,3)=="ftp"){
    xurl <- RCurl::getURL(shape_url)
    for (i in paste(layer, shapefile_ext, sep = "")) {
      xlogic <- c(xlogic, grepl(i, xurl))
    }
  } else if(substr(shape_url,1,4)=="http"){
    for (i in paste(shape_url,layer, shapefile_ext, sep = "")) {
      xlogic <- c(xlogic,httr::HEAD(i)$status==200)
    }  
  }
  
 
  shapefiles <- paste(shape_url, layer, shapefile_ext, 
                      sep = "")[xlogic]
  outfiles <- paste(outfolder, "/", layer, shapefile_ext, 
                    sep = "")[xlogic]

  if (sum(xlogic) > 0) {
    for (i in 1:length(shapefiles)) {
      x <- suppressWarnings(httr::GET(shapefiles[i], 
                                      httr::write_disk(outfiles[i],
                                                       overwrite = TRUE)))
      
      dwnld_file <- strsplit(shapefiles[i], "/")[[1]]
      dwnld_file <- dwnld_file[length(dwnld_file)]
      
      print(paste0("Downloaded ", dwnld_file, " to ", 
                   outfiles[i], "."))
    }
  }
  else {
    stop("An Error has occured with the input URL or 
              name of shapefile")
  }
}

And to see that it works again:

#Download the NH State Boundaries
download_shp("ftp://ftp.granit.sr.unh.edu/pub/GRANIT_Data/Vector_Data/Administrative_and_Political_Boundaries/d-political",
                   "pba")

## [1] "Downloaded pba.shp to ./pba.shp."
## [1] "Downloaded pba.shx to ./pba.shx."
## [1] "Downloaded pba.dbf to ./pba.dbf."
## [1] "Downloaded pba.prj to ./pba.prj."

#Read shapefiles in SpatialPolygonsDataFrame
NHBnd <- readOGR(".","pba")

## OGR data source with driver: ESRI Shapefile 
## Source: "/var/host/media/removable/SD Card/jwhollister.com/content/post", layer: "pba"
## with 773 features
## It has 8 fields
## Integer64 fields read as strings:  FNODE_ TNODE_ LPOLY_ RPOLY_ PB_ PB_ID

#Plot it
plot(NHBnd)