I've acquired a gridded NetCDF file that the product developers claim is CF-compliant. I ran it through a CF compliance checker and received some errors (see below), all were related to the fact that the compliance check did not recognize the standard or some variable names, but nothing to do with the actual structure of the file. Based on this, one would assume it could be displayed properly in Mc-V, but McIDAS-V does not recognize it as a gridded file? Why is this occurring? I placed a copy of the file at: ftp://ftp.ssec.wisc.edu/pub/incoming/CE ... -200808.nc
CHECKING NetCDF FILE: /tmp/30746.nc
=====================
Using CF Checker version 1.4.0
Using Standard Name Table Version 13 (2010-03-11T11:12:25Z)
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Checking variable: cldicediam_mon_day-night
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ERROR (2.3): Invalid variable name - cldicediam_mon_day-night
ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Ice Particle Effective Diameter - DAY-NIGHT'
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Checking variable: cldtemp_mon_day-night
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ERROR (2.3): Invalid variable name - cldtemp_mon_day-night
ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Cloud Effective Temperature - DAY-NIGHT'
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Checking variable: cldpress_mon_day
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ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Cloud Effective Pressure - DAY'
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Checking variable: lat
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Checking variable: scalar
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ERROR (3.3): Invalid standard_name: scalar
ERROR (3.1): Invalid units: unitless
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Checking variable: iwp_mon_day-night
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ERROR (2.3): Invalid variable name - iwp_mon_day-night
ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Ice Water Path - DAY-NIGHT'
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Checking variable: cldtemp_mon_day
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ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Cloud Effective Temperature - DAY'
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Checking variable: cldwatrad_mon_day
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ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Water Particle Radius - DAY'
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Checking variable: cldtau_mon_day-night
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ERROR (2.3): Invalid variable name - cldtau_mon_day-night
ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Cloud Visible Optical Depth - log - DAY-NIGHT'
ERROR (3.1): Invalid units: unitless
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Checking variable: lon
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Checking variable: lwp_mon_day
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ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Liquid Water Path - DAY'
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Checking variable: cldtau_mon_day
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ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Cloud Visible Optical Depth - log - DAY'
ERROR (3.1): Invalid units: unitless
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Checking variable: cldwatrad_mon_day-night
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ERROR (2.3): Invalid variable name - cldwatrad_mon_day-night
ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Water Particle Radius - DAY-NIGHT'
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Checking variable: cldphase_mon_day-night
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ERROR (2.3): Invalid variable name - cldphase_mon_day-night
ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Cloud Particle Phase - DAY-NIGHT'
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Checking variable: cldarea_mon_day-night
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ERROR (2.3): Invalid variable name - cldarea_mon_day-night
ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Cloud Area Fraction - DAY-NIGHT'
ERROR (3.1): Invalid units: Percent
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Checking variable: lwp_mon_day-night
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ERROR (2.3): Invalid variable name - lwp_mon_day-night
ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Liquid Water Path - DAY-NIGHT'
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Checking variable: cldphase_mon_day
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ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Cloud Particle Phase - DAY'
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Checking variable: iwp_mon_day
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ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Ice Water Path - DAY'
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Checking variable: cldicediam_mon_day
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ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Ice Particle Effective Diameter - DAY'
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Checking variable: cldarea_mon_day
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ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Cloud Area Fraction - DAY'
ERROR (3.1): Invalid units: Percent
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Checking variable: cldpress_mon_day-night
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ERROR (2.3): Invalid variable name - cldpress_mon_day-night
ERROR (3.3): Invalid syntax for 'standard_name' attribute: 'Cloud Effective Pressure - DAY-NIGHT'
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Checking variable: time
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ERRORS detected: 33
WARNINGS given: 0
McIDAS-V not recognizing NetCDF gridded data
Re: McIDAS-V not recognizing NetCDF gridded data
Using NetCDF ToolsUI, I find that the NetCDF library does not recognize anything in the file as a "grid".
I suspect it is because of the dimension named "scalar" -- it does not know what do to with that since it is not a "coordinate system" type of variable. I have no solution to this, other than rewriting the file with this dimension removed.
Also, "valid_range_min" and "..max" are NOT CF attributes. They need "valid_min" and "valid_max" (or "valid_range"). They should be careful in mixing "types" between the variables and the "range" values -- there is no reason whatsoever to specify a value range as a "short" when the variable is a "float" (unless scaling is used).
In addition "unitless" is not a valid "unit" type.
Variable names may note contain a hypen (to quote the CF 1.4 doc: "Variable, dimension and attribute names should begin with a letter and be composed of letters, digits, and underscores.") The NetCDF library is a little lenient about enforcing this, however....
I believe they have misused the "standard_name" attribute -- unless they have submitted all these names to be entered in the blessed table...? I note that, again, the CF1.4 documentation defines the format of a "Standard Name" to be: "A standard name contains no whitespace and is case sensitive. "
That's all for now....
I suspect it is because of the dimension named "scalar" -- it does not know what do to with that since it is not a "coordinate system" type of variable. I have no solution to this, other than rewriting the file with this dimension removed.
Also, "valid_range_min" and "..max" are NOT CF attributes. They need "valid_min" and "valid_max" (or "valid_range"). They should be careful in mixing "types" between the variables and the "range" values -- there is no reason whatsoever to specify a value range as a "short" when the variable is a "float" (unless scaling is used).
In addition "unitless" is not a valid "unit" type.
Variable names may note contain a hypen (to quote the CF 1.4 doc: "Variable, dimension and attribute names should begin with a letter and be composed of letters, digits, and underscores.") The NetCDF library is a little lenient about enforcing this, however....
I believe they have misused the "standard_name" attribute -- unless they have submitted all these names to be entered in the blessed table...? I note that, again, the CF1.4 documentation defines the format of a "Standard Name" to be: "A standard name contains no whitespace and is case sensitive. "
That's all for now....