Hi, John!
On Wed, Mar 10, 2010 at 9:27 AM, john caron <caron at unidata.ucar.edu> wrote:
> It appears that d0 is a time dimension? If so, CF would require a time
> coordinate for it.
I don't know its precise physical meaning but the real interesting
part is that lat/lon positions are recorded in 3-D array since most
EOS swath has 2-D array lat/lon coordinate variables. The data has a
separate time variable in 3-D array as well.
In CF-1.4 two dimensional coordinate system, I believe that the name
and the number of dimensions are not significant as long as they are
unique enough to associate between coordinate variables and variables.
> In any case, its necessary to distinguish between "CF
> compliant" and "able to be georeferenced by generic programs using CF
> metadata". The latter is more stringent, and at the moment i dont think your
> dataset has enough info.
I agree that the latter is more stringent. I often feel frustrated by
the gap between "CF-compliant"-ness of data and "geo-referencing
capability of the real softwares using CF metadata". However, I think
my data has enough information to be plotted on the World map if
softwares are smart enough to pick up lat/lon coordinate variables
represented in 3-D, 4-D, ... n-D.
>
>
> H. Joe Lee wrote:
>>
>> Thanks, Karl! Maybe, I think it's good to mention this possibility
>> in the CF document: coordinate variables can be arbitrary n-Dimension
>> arrays where n > 1.
>>
>> Regarding the 3rd dimension, the 3-D lat/lon coordinate variables
>> have dimension names like below.
>>
>> 447 (Number of HourBoxes) x 3 (1.0 deg. Colat Zones: 178 - 180) x
>> 360 (1.0 deg. longitude regions)
>>
>>
>> --
>> +1(217)265-7710
>> http://hdfeos.org
>>
>>
>>
>> On Fri, Mar 5, 2010 at 4:14 PM, Karl Taylor <taylor13 at llnl.gov> wrote:
>>
>>>
>>> Hi,
>>>
>>> This file looks CF-compliant to me. I don't think it has to be 2-d.
>>> Like
>>> John Caron, I am mildly curious what the 3-dimensions represent.
>>>
>>> regards,
>>> Karl
>>>
>>> On 05-Mar-10 12:30 PM, H. Joe Lee wrote:
>>>
>>>>
>>>> Hi,
>>>>
>>>> I have a satellite data that stores lat / lon information in 3-D
>>>> array and I'm wondering how such data can meet the CF convention.
>>>>
>>>> Following the
>>>> http://*cf-pcmdi.llnl.gov/documents/cf-conventions/1.4/ch05s02.html
>>>> page example convention, here's the description of my data:
>>>>
>>>> -------------------------
>>>> dimensions:
>>>>
>>>> d0 = 447 ;
>>>> d1 = 3 ;
>>>> d2 = 360;
>>>> lev = 18 ;
>>>>
>>>> variables:
>>>> float V(lev,d0,d1,d2) ;
>>>> T:long_name = "Precipitable Water" ;
>>>> T:units = "cm" ;
>>>> T:coordinates = "lon lat" ;
>>>> float lev(lev) ;
>>>> lev:long_name = "pressure level" ;
>>>> lev:units = "hPa" ;
>>>> float lon(d0,d1,d2) ;
>>>> lon:long_name = "longitude" ;
>>>> lon:units = "degrees_east" ;
>>>> float lat(d0,d1,d2) ;
>>>> lat:long_name = "latitude" ;
>>>> lat:units = "degrees_north" ;
>>>> -----------------------------------------------
>>>>
>>>> My question is, should lat / lon coordinate variables be always 2-D
>>>> array in CF-convention for two dimensional coordinate system?
>>>>
>>>> Thanks,
>>>>
>>>> --
>>>> +1(217)265-7710
>>>> http://*hdfeos.org
>>>> _______________________________________________
>>>> CF-metadata mailing list
>>>> CF-metadata at cgd.ucar.edu
>>>> http://*mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>
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>
>
Received on Wed Mar 10 2010 - 09:26:40 GMT
