The original R-GRASS interface (R. S. Bivand 2000; Neteler and Mitasova 2008) was designed to move raster and later vector data between R and GRASS GIS. To do this, use was made of intermediate files, often using the external GDAL library on both sides. On the R side, the rgdal package was used, interfacing GDAL and PROJ as GRASS GIS also did. The GRASS commands r.in.gdal, r.out.gdal, v.in.ogr and v.out.ogr were matched by rgdal functions using the same underlying external libraries: