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[IDV #LMW-673348]: Ocean glider data open as Track file problem
- Subject: [IDV #LMW-673348]: Ocean glider data open as Track file problem
- Date: Mon, 07 Feb 2011 20:19:41 -0700
> Hello,
>
> I am Matias Bonet I work for the AODN (Australian ocean data network
> http://portal.aodn.org.au/webportal/) based at the University of Tasmania.
> We are using netcdf/CF convention to define Glider trajectories. The problem
> comes when we want to open this files in IDV.
>
> Here we have a thredds catalog with data from different gliders (Slocum and
> Seagliders)
> http://opendap-vpac.arcs.org.au/thredds/catalog/IMOS/ANFOG/catalog.html
>
> As the Australian ocean data network we receive the data from all the
> gliders around australia. Ups sorry, a glider is a submarine
> http://www.youtube.com/watch?v=YFyu3Lm_xlM&feature=related I also attach a
> capture using IDV about how it look like.
>
>
> The problem is that the track file reader does not follow the CF
> conventions.
> http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.5/ch05s05.html There are
> a few things that are not right:
>
> - Is using the variable names instead of variable attributes even in this
> case we have the same names but in upper case and does not work either.
> - The variable for the Z index must be named Altitude for the IDV to be
> interpreted and also we have to change the units to -1.0meters to go above
> the sea level.
>
>
> I added a NCML file to modify our netcdf files the changes basically are:
>
> - Change TIME dimension to lower case (imply change all the shapes to
> time in lower case).
> - Change of LATITUDE and LONGITUDE to lower case.
> - Change variable DEPTH to altitude and units of it to -1.0meters.
>
> The changes are not really hard (i thing). Is a matter of add to lower in
> the string comparation and also a check to altitude or depth and in case
> that the variable name is depth then use tha attribute positive="UP or
> DOWN".
>
Hi Matias,
The problem is not simply up case or lower case here. The IDV depends
on the CDM library to define the
trajectory data type, and I believe the ncml wrapper you created actually
transfers your glider dataset into a recognizable trajectory data type. The CDM
also moves to the feature type to better support the trajectory dataset,
and I want to make sure your ncml file is good too. If you just want to display
in the IDV, you can use the ncml to define a new glider data source type, this
may help you too.
Yuan
> I added to the link to the CF conventions for trajectories
> http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.5/ch05s05.html
>
> Thank you very much.
>
> Matias.
>
>
Ticket Details
===================
Ticket ID: LMW-673348
Department: Support IDV
Priority: Normal
Status: Open