I/O for geographic data (shapefiles, etc.)

Introduction#

See also Introduction to Geographical Maps and Input and Output

Import and Export Shapefiles

With the rgdal package it is possible to import and export shapfiles with R. The function readOGR can be used to imports shapfiles. If you want to import a file from e.g. ArcGIS the first argument dsn is the path to the folder which contains the shapefile. layer is the name of the shapefile without the file ending (just map and not map.shp).

library(rgdal)
readOGR(dsn = "path\to\the\folder\containing\the\shapefile", layer = "map") 

To export a shapefile use thewriteOGR function. The first argument is the spatial object produced in R. dsn and layer are the same as above. The obligatory 4. argument is the driver used to generate the shapefile. The function ogrDrivers() lists all available drivers. If you want to export a shapfile to ArcGis or QGis you could use driver = "ESRI Shapefile".

writeOGR(Rmap, dsn = "path\to\the\folder\containing\the\shapefile", layer = "map",
         driver = "ESRI Shapefile" )

tmap package has a very convenient function read_shape(), which is a wrapper for rgdal::reagOGR(). The read_shape() function simplifies the process of importing a shapefile a lot. On the downside, tmap is quite heavy.