2

I have a directory that contains around 700 .shp files. I want to create a map in R that displays all of them. The easiest way i could think to do this was to bind them all together and then use ggplot2 to create a map. here is my code to read the files and create a list containing the files:

dir <- "./Basins/separate_basins/"
basins <- list.files(dir, pattern = "\\.shp$")
basins <- unique(file_path_sans_ext(basins))
cord <- "+init=epsg:2163"
templist <- list()

for (i in basins){ 

  thisbasin <- readOGR(dsn=dir, layer=i)
  thisbasin <- spTransform(thisbasin, cord)
  templist[[i]] <- data.frame(thisbasin)
}

I then try to use the bind function to bind all of the components in the list together: test_bind <- bind(templist) Then I tried to test if this works using `plot(test_bind) but it prints like this: enter image description here

I want to display the polygons that are present in the original .shp files. how can I fix this?

3

Your code is coercing the data into a data.frame before piping into the list object so, don't do that. I would recommend some small changes to your code and then using do.call on the list to bind the results into a single sp SpatialPolygonsDataFrame object.

templist <- list() 
  for (i in 1:length(basins)){ 
    thisbasin <- readOGR(dsn=dir, layer=basins[i])
    templist[[i]] <- spTransform(thisbasin, cord)
  }
basins <- do.call("rbind", templist)

At this point, since you want to plot using ggplot2, I would recommend coercing to an sf object.

  • 1
    BTW if you go to sf best to start with sf x <- do.call(rbind, lapply(list.files(dir, pattern = "shp$", full.names = TRUE), sf::read_sf)) - will be faster, no need for dropping .shp etc. – mdsumner Nov 28 '18 at 6:19

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