Dear all,
We have a NetCDF file that fails the CF compliance checker on the BADC
website:
http://titania.badc.rl.ac.uk/cgi-bin/cf-checker.pl
The failure concerns the use of 'flag_values' to describe a flag
variable called 'mask'.
> Checking variable: mask
> ------------------
> ERROR: Attribute flag_values of incorrect type
>
Following this up we ran into a problem. On the list of attributes in
CF-1.0 appendix A, flag_values is described as a string, but all the
examples I've seen, including that in CF-1.0, section 3.5, use a list
(vector) of valid numeric values (presumably matching the variable
type).
Part of the the ncdump for our file looks like this:
byte mask(time, lat, lon) ;
mask:long_name = "sea/land/lake/ice field composite mask" ;
mask:_FillValue = -128b ;
mask:flag_values = 1b, 2b, 4b, 8b ;
mask:flag_meanings = "sea land lake ice" ;
I think flag_values should be numeric rather than a string. The CF-1.0
standard should be consistent either way...
Thanks,
John
--
John Stark SST and Sea Ice Scientist
Met Office FitzRoy Road Exeter EX1 3PB United Kingdom
Tel: +44 (0)1392 885059 Fax: +44 (0)1392 885681
Received on Thu Apr 19 2007 - 04:36:59 BST
