KML to GeoJSON conversion in R

kml_to_geojson.R

#########################################################
#####  Script to load in KML and output to GeoJSON  #####
#####  Robin Edwards, geotheory.co.uk, @geotheory   #####
#########################################################

# This script accepts a simple KML file (e.g. from Google Earth or Scribblemaps.com) and converts to GeoJSON.
# It will not accept KMLs with multiple geometries - they must be entirely of points, paths or polygons, 
# or a primitive geometry (such as rectangle or circle)
# 
# How to run:
#  - update the working directory path in the setwd() below to the script's parent folder
#  - copy the KML file you want to convert to the same folder and rename it 'data.kml'
#  - navigate to folder in OSX Console / Windows command prompt / etc
#  - type 'RScript kml_to_geojson.R'
#  - a file named 'data.geojson' will be writted (overwritten if already exists)
# 
# If RScript fails to run in Windows you may need to add its executable folder path to the 'PATH' list
# in Environmental Variables.


require(rgdal)
require(stringr)

setwd('C:/Folder Path')   # UPDATE TO SCRIPT FOLDER

map = readOGR("data.kml", layer=ogrListLayers("data.kml"), verbose=T, 
      drop_unsupported_fields=T, dropNULLGeometries=T, stringsAsFactors=F)

# removes HTML code that can appear in Description field (e.g. scribblemaps)
if(any(str_detect(map@data[,2], "<FONT"))){
  try(map@data[,2] <- str_match(map@data[,2], "<FONT.*>(.*)</FONT>")[,2], silent=T)
}
  
unlink("data.geojson")
writeOGR(map, "data.geojson", "data", driver = "GeoJSON")

For anyone using this converter, you need to modify the writeOGR function to this:

writeOGR(map, "data.geojson", "data", driver = "GeoJSON", check_exists = FALSE)

By adding: check_exist = FALSE , you can avoid the "Cannot Open File" error.