Re: [thredds] Time aggregating Profile Data from multiple casts

• To: Ajay Krishnan - NOAA Affiliate <ajay.krishnan@xxxxxxxx>
• Subject: Re: [thredds] Time aggregating Profile Data from multiple casts
• From: Sean Arms <sarms@xxxxxxxx>
• Date: Fri, 25 Mar 2016 11:33:40 -0600

Greetings Ajay,

Unfortunately, I do not have any advice for aggregations or
FeatureCollections on TDS 4.2.x - things have changed so much since then,
especially for serving point data via the TDS. However, the use of netcdf
files for point data within the TDS heavily relies on the data following
the CF 1.6 discreet sampling geometry standard.  The example files you
pointed to state they follow the Profile DSG:

http://cfconventions.org/Data/cf-conventions/cf-conventions-1.6/build/cf-conventions.html#idp8350112

but they do not quite follow that standard. For example, the dimension
casts is essentially the profile identifier (the variable wod_unique_cast
is the profile id). In this case, all data variables should have the
dimension casts as their first dimension. At that point, you would be able
to aggregate the files on the casts dimension and things should work. NcML
cannot be used to "reshape" data variables, so unfortunately this is a job
that would require a rewrite of the data.

Sorry I don't have better news at the moment - maybe someone else has dealt
with this and would like to chime in?

Sean


On Thu, Mar 24, 2016 at 2:49 PM, Ajay Krishnan - NOAA Affiliate <
ajay.krishnan@xxxxxxxx> wrote:

> Hi TDS Users,
>
> I have monthly data from different CTD casts bundled into a single netCDF
> file. I am looking at creating a virtual aggregation of such monthly files
> spanning several decades. What's the best way to implement this using TDS?
>
> Can I do this using Feature Collections? I have not been successful in
> doing a time aggregation using NcML.
>
> I have some sample data at:
> http://data.nodc.noaa.gov/thredds/catalog/testdata/wod_test/catalog.html
>
> Running TDS 4.2.10
>
> Thanks,
> Ajay
>
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  • [thredds] Time aggregating Profile Data from multiple casts
    • From: Ajay Krishnan - NOAA Affiliate