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

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
>
>
>
>