ncap2 scripts and attributes with dots in their name

[Daniel Neumann]

Hey,

Happy new year!

Some global attributes of a netCDF I am working with contain a dot in their name. E.g.:

SURF_ugN_NOX.coordinates="abc";

I would like to work with these global attributes in a ncap2 scripts. But none of these solutions work:

global@SURF_ugN_NOX.coordinates.ram_delete();
global@`SURF_ugN_NOX.coordinates`.ram_delete();
global@"SURF_ugN_NOX.coordinates".ram_delete();
global@'SURF_ugN_NOX.coordinates'.ram_delete();

Does there exist a workaround? Or should I rename these attributes first -- e.g. with ncatted.

Cheers,
Daniel

[henry Butowsky]

Hi Daniel,
you need to replace the "." with @
the "." in ncap2 is used to specify a ncap2 method.
e.g
SURF_ugN_NOX@coordinates="abc";
or
'global@'SURF_ugN_NOX.coordinates'.ram_delete();

To use the "." in a name you need to quote the var/att name with "'" as I have done above.
...Henry

[Daniel Neumann]

Hi Henry,

Thanks for the quick reply.

you need to replace the "." with @
the "." in ncap2 is used to specify a ncap2 method.
e.g
SURF_ugN_NOX@coordinates="abc";
or
'global@'SURF_ugN_NOX.coordinates'.ram_delete();

To use the "." in a name you need to quote the var/att name with "'" as I have done above.

Unfortunately, both solutions do not work (global@SURF_ugN_NOX@coordinates and 'global@'SURF_ugN_NOX.coordinates'; see bottom of this post). Probably, I explained my issue wrongly. This is my cdl file definition:

netcdf test1 {
dimensions:
        time = UNLIMITED ; // (4 currently)
        lat = 4 ;
        lon = 4 ;
variables:
        float SURF_ugN_NOX(time, lat, lon) ;
                SURF_ugN_NOX:_FillValue = 9.96921e+36f ;
                SURF_ugN_NOX:coordinates = "lat lon" ;
                SURF_ugN_NOX:units = "mmol N/m**2/day" ;

// global attributes:
                :vert_coord = "atmosphere_hybrid_sigma_pressure_coordinate" ;
                :SURF_ugN_NOX._FillValue = 9.96920996838687e+36 ;
                :SURF_ugN_NOX.coordinates = "lat lon" ;
                :SURF_ugN_NOX.units = "ugN/m3" ;
}

All attributes of each variable are duplicated as global attributes due to an issue with a THREDDS server, from which I downloaded these data. I want to remove the duplicate global attributes.

Here is, what I tried in ncap2 scripts. The comment lines indicate the resulting error.

global@SURF_ugN_NOX.coordinates.ram_delete();
      /* test2.ncap:1:14: expecting FUNC, found 'coordinates' */
global@'SURF_ugN_NOX.coordinates'.ram_delete();
      /* testA.ncap line 1, column 11: unexpected character 'g' */
global@"SURF_ugN_NOX.coordinates".ram_delete();
      /* testA.ncap line 1, column 11: unexpected character 'g' */
global@`SURF_ugN_NOX.coordinates`.ram_delete();
      /* testA.ncap line 1, column 11: unexpected character 'g' */
global@SURF_ugN_NOX\.coordinates.ram_delete();
      /* testA.ncap line 1, column 23: unexpected character '\' */
global@SURF_ugN_NOX@coordinates.ram_delete();
      /* test2.ncap:1:13: unexpected token: global@coordinates */
'global@'SURF_ugN_NOX.coordinates'.ram_delete();
      /* testA.ncap line 1, column 12: unexpected character ''' */

[Daniel Neumann]

Actually, I am confused about the usage of ram_delete(). I understood the definition

ram_delete()
Deletes a RAM variable or an attribute

as delete a RAM variable or delete any attribute (not a newly created attribute). But

global@vert_coord.ram_delete();

yields

ncap2: WARNING utl_cls::fnd(): ram_delete unable to find variable: global@vert_coord