The function is vectorized because why not, but probably only ever will be
used on single element vectors of character strings.
Note that no sanitizing is done on inputs, we literally just 'OGRSpatialReference.SetFromUserInput(crs)' and
give the output as WKT. If it's an error in GDAL it's an error in R.
Common inputs are WKT variants,
'AUTH:CODE's e.g. 'EPSG:3031', the 'OGC:CRS84' for long,lat WGS84, 'ESRI:code' and other authority variants, and
datum names such as 'WGS84','NAD27' recognized by PROJ itself.
See help for 'SetFromUserInput' in 'OGRSpatialReference', and 'proj_create_crs_to_crs'.
c.proj_create_crs_to_crs
c.proj_create
SetFromUserInput