Thanks, Jim, I will take it to ACDD.
Mary Jo
On Tue, 16 Aug 2016, Jim Biard wrote:
> Date: Tue, 16 Aug 2016 12:43:57 -0400
> From: Jim Biard <jbiard at cicsnc.org>
> To: cf-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] Best practice to include spatial resolution for
> projected data
>
> Mary Jo,
>
> It's a problem that doesn't currently have an official solution. The
> geospatial_lat/lon_resolution are from the ESIP Attribute Convention for
> Dataset Discovery (ACDD) <http://wiki.esipfed.org/index.php/ACDD>, but they
> haven't thought through to a generalization yet. You could make your own
> attributes geospatial_resolution or geospatial_x_resolution and
> geospatial_y_resolution, or you could think of longitude as being ~x and
> latitude as ~y and use the existing attributes. You can also query the ESIP
> people and request that they add a new set of attributes that would handle
> this. I think the CF community likely considers this to be more of an ACDD
> issue.
>
> Grace and peace,
>
> Jim
>
> On 8/16/16 12:33 PM, Mary Jo Brodzik wrote:
>
>>
>> I am producing a gridded data set using CF-1.6 conventions. In a given
>> file, the data are projected onto one of three possible projections:
>> Northern or Southern Lambert Azimuthal Equal Area (LAEA), or Cylindrical
>> Equal-Area (CEA). With each data variable in the file, I do include the
>> grid_mapping attribute and I am populating my grid_mapping variable with
>> the required projection information as listed here:
>>
>> http://cfconventions.org/cf-conventions/v1.6.0/cf-conventions.html
>>
>> Also in a given file, the spatial resolution will be one of 25, 12.5, 6.25
>> or 3.125 km, and although this is obvious from the x and y dimension
>> variable values, I am looking for a place to include the spatial resolution
>> for a human who is reading the metadata.
>>
>> I assume an attribute in the grid_mapping variable would be the place for
>> this. At first I thought it was one of the "scale_factor*" attributes,
>> e.g. "scale_factor_at_projection_origin", but for CEA, this would be a
>> misnomer, since the value is the scale at true latitude, not the projection
>> origin at all. Also, the convention says to include "either
>> standard_parallel or scale_factor_at_projection_origin", so now I'm
>> beginning to think these "scale_factor_*" attributes are not the correct
>> place at all for this information.
>>
>> I see in the NCEI template file for gridded data
>>
>> https://www.nodc.noaa.gov/data/formats/netcdf/v2.0/grid.cdl
>>
>> that they recommend global attributes like "geospatial_lat_resolution" and
>> "geospatial_lon_resolution", with a string value of "0.1 degree" or "100
>> meters" which is almost what I am looking for, but of course since I have
>> projected data it would not be "lat" or "lon".
>>
>> Can anyone recommend a best practice for my projected data case that I can
>> follow?
>>
>> Thank you,
>> Mary Jo Brodzik
>>
>> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>> Mary Jo Brodzik, Senior Associate Scientist, 303-492-8263
>> NSIDC/CIRES, Univ. of Colo. at Boulder, 449 UCB, Boulder, CO 80309-0449
>> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>> _______________________________________________
>> CF-metadata mailing list
>> CF-metadata at cgd.ucar.edu
>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>
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>
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Mary Jo Brodzik, Senior Associate Scientist, 303-492-8263
NSIDC/CIRES, Univ. of Colo. at Boulder, 449 UCB, Boulder, CO 80309-0449
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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