[CF-metadata] machine-accessible CF compliance checker?

From: stephen.pascoe at stfc.ac.uk <stephen.pascoe>
Date: Wed, 29 Feb 2012 15:31:45 +0000

Hi Phil,

So far my role has simply been to package and deploy Rosalyn's cfchecker code, therefore I really don't know to what extent it needs the real NetCDF.

I think an alternative checker (i.e. codebase) is a bad idea because they might give contradictory results. I would suggest several options:

 1. Work on making the cfchecker package easier to install so that users can run it on their real NetCDF. A user would have to know how to install python packages, compile UDUNITS and edit a config file.
 2. Add a "headers-only" feature to Rosalyn's code so that user's can create dummy NetCDF with ncgen to upload to one of the online checkers.
 3. As an addition to #2, add a feature to Rosalyn's code, or the CGI wrapper, to upload CDL.

I am willing to do #1, if people think it would meet user's needs, but it would have to be added to my ever-expanding TODO list :-). Rosalyn, do you have any comments on #2&3?

Cheers,
Stephen.

---
Stephen Pascoe  +44 (0)1235 445980
Centre of Environmental Data Archival
STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot OX11 0QX, UK
-----Original Message-----
From: Bentley, Philip [mailto:philip.bentley at metoffice.gov.uk] 
Sent: 29 February 2012 14:56
To: Pascoe, Stephen (STFC,RAL,RALSP); cf-metadata at cgd.ucar.edu
Subject: RE: [CF-metadata] machine-accessible CF compliance checker?
Hi Stephen,
I may well be wrong, but I suspect that one of the reasons - perhaps the
main reason - why folks would like access to a stand-alone cfchecker
utility is the large size of their netcdf files. (It's certainly the
reason we use a local version.)
As you know only too well (from CMIP5), most of the netcdf files we're
dealing with these days run into the high 100s of MB or low GBs. It's
not really practical to upload such files in order to perform a CF
compliance check. At least not on more than a few files.
I wonder, therefore, if a possible solution is to develop an alternative
checker utility that operates not on the netcdf file itself, but rather
on the header info output by the ncdump -h command. Generating and
uploading those would be trivial by comparison.
Off the top of my head (and having given it almost zero thought!) the
only test that I can think of which examines the actual data values is
the check for coord vars being monotonic. But I suspect there are others
I'm unaware of.
If nothing else, such a utility might have some value as a 'first pass'
checker.
Any mileage in this? Apologies if it's already done the rounds!
Regards,
Phil
 
> -----Original Message-----
> From: cf-metadata-bounces at cgd.ucar.edu 
> [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of 
> stephen.pascoe at stfc.ac.uk
> Sent: 29 February 2012 11:39
> To: christopher.s.lynnes at nasa.gov; cf-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] machine-accessible CF compliance checker?
> 
> Hi Christopher,
> 
> Are you looking for a way to run the cfchecker locally or 
> submit checking requests to one of the websites in a script?
> 
> I think both would be possible with a little help.  The 
> cfchecker is now available on the Python Package Index at 
> http://pypi.python.org/pypi/cfchecker.  It needs a little 
> help to work out of the box -- you need to configure UDUNITS 
> and the location of several CF XML files.  It's on my 
> long-term TODO list to make this configuration easier.
> 
> Also the CF-checker at BADC and NCAS-CMS has a very simple 
> HTTP interface that could be scripted.
> 
> Cheers,
> Stephen.
> 
> ---
> Stephen Pascoe  +44 (0)1235 445980
> Centre of Environmental Data Archival
> STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot 
> OX11 0QX, UK
> 
> 
> -----Original Message-----
> From: cf-metadata-bounces at cgd.ucar.edu 
> [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of 
> Lynnes, Christopher S. (GSFC-6102)
> Sent: 28 February 2012 16:03
> To: cf-metadata at cgd.ucar.edu
> Subject: [CF-metadata] machine-accessible CF compliance checker?
> 
> I know about the web sites where you use a form to upload 
> files to check CF compliance, but is there a service 
> somewhere that can be accessed by a script?
> --
> Dr. Christopher Lynnes     NASA/GSFC, Code 610.2    phone: 
> 301-614-5185
> 
> 
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Received on Wed Feb 29 2012 - 08:31:45 GMT