Generate a table of all extended dimension attributes. For now that means interpretation of any "time" dimension.
nc_extended(x, ...)
# S3 method for character
nc_extended(x, ...)
# S3 method for NetCDF
nc_extended(x, ...)
# S3 method for ncdf4
nc_extended(x, ...)
filename or handle
ignored currently
data frame of extended dimension attribute information