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Re: Help by using IDV to display 2D lat/long grid file

John,

Thank you for your help. You're absolutely right. The key problem was
that at least one of the dataset variables (like Time in [1]) should
have the "coordinate" attribute.

I'm sorry that I wasn't careful in making the output that conforms to
CF-convention.

-- Joe



On Thu, Jan 29, 2009 at 5:30 PM, John Caron <address@hidden> wrote:
> Hi Kent:
>
> Yes, IDV can handle 2D lat/lons.
>
> In looking at dataset #2, in order to be CF-compliant, since you have 2D 
> auxiliary coordinate
> variables, you need to add to each data variable:
>
>  :coordinates = "lat lon";
>
> its also better not to use "lat", "lon" as the dimension names, although that 
> is optional.
>
> In looking at dataset #1, we are picking up the 2d variables, as well as the 
> 3D variables on
> pressStd vertical level. We would pick up the 3D variables on H2OPressureLev 
> if the variable
> pressH2O was renamed H2OPressureLev and so was a coordinate variable. We pick 
> up these because the
> variable Time has
>
>  :coordinates = "lat lon";
>
> We then use that for any other data variable. Technically, you should put 
> that attribute on all data
> variables.
>
> Ill be out of town for a week, so may not be able to follow up on this until 
> then.s
> John
>
>
> MuQun Yang wrote:
>> Hi John,
>>
>> How are you? We've gotten more adventures with IDV to display some files
>> with OPeNDAP. The question basically boils down to if IDV can display 2D
>> lat/long grid file. If not, what's your plan for that? This will be
>> common for different projection grid files. See the details below.
>>
>> Thank you very much!
>>
>> Kent
>>
>> -------------------  from Joe Lee -----
>>
>> I'm trying to visualize 2 files below with IDV:
>>
>> [1]
>> http://hdfdap.hdfgroup.uiuc.edu:8080/cgi-bin/nph-dods/AIRS.2008.04.16.201.L2.RetStd.v5.2.2.0.G08109135217.hdf
>>
>>
>> [2]
>> http://hdfdap.hdfgroup.uiuc.edu:8080/cgi-bin/nph-dods/MYD09A1.A2002185.h00v08.005.2007175015530.hdf
>>
>>
>> [1] is a swath file and [2] is a grid file with sinusoidal projection.
>> Both have 2-D lat/long dimension variable.
>>
>> In short, I could display [2] but not [1]. Thus, I got a few questions
>> about the IDV and the CF-convention.
>> I can see the main difference between the two is the existence of Time
>> dimension variable.
>>
>> Can't IDV display 2D lat/lon Grid without time dimension?
>> If not, does IDV always require a Time dimension variable to display
>> Swath data properly?
>>
>> To assess the problem more carefully, you may want to view DAS/DDS
>> outputs of the data files using the following page:
>>
>>  http://hdfdap.hdfgroup.uiuc.edu:8080/hdf4.html
>>
>>
>> Regards,
>>
>> -- Joe
>>
>>
>>
>>
>
>