Folks,
There certainly are a fair number of "grid" featureTypes that also
would benefit from FillValues being allowed on aux coordinate
variables.
Consider this NOAA coastal ocean model grid for Chesapeake Bay:
http://screencast.com/t/Humzu7F69
and a zoom in on one of the tributaries:
http://screencast.com/t/eMLBhHEHO1
Although the lon,lat and bathymetry values shown here can be
represented by 2D arrays with fillValues, it's impossible to fill in
the missing values with any kind of smooth function. Each tributary
is being mapped from computational space to coordinate space using
separate conformal transformations.
This is a fairly common case, and it would be too bad to exclude it
from being described with CF conventions.
-Rich
On Mon, Mar 26, 2012 at 2:09 PM, Randy Horne <rhorne at excaliburlabs.com> wrote:
> Jonathan:
>
> We are putting in fill values for these off-earth points in the data variables.
>
>
> very respectfully,
>
> randy
>
>
> Randy C. Horne (rhorne at excaliburlabs.com)
> Principal Engineer, Excalibur Laboratories Inc.
> voice & fax: (321) 952-5100
> url: http://www.excaliburlabs.com
>
> PGP Public Keys available at:
> A HREF="http://pgpkeys.mit.edu:11371">MIT's Key Server</A>
>
> ---------- Original Message ----------------------------------
> From: Jonathan Gregory <j.m.gregory at reading.ac.uk>
> Date: ?Mon, 26 Mar 2012 18:35:19 +0100
>
>>Dear all
>>
>>Regarding Randy's reply:
>>
>>> In the case of GOES-R (and also Meteosat) our coordinate variable values are N/S elevation angle and E/W scanning angle, which can be syntactically valid values albeit off the disk of the earth.
>>
>>In this case, are there data values, or is the data missing at non-existent
>>points?
>>
>>Regarding Nan's point, I would say that we do want CF to be inclusive. It
>>would be a mistake to impose irrelevant requirements that deterred people
>>from using the convention. In the case you mention, the chapter 9 convention
>>for profiles wouldn't allow you to have missing data in Z; it permits missing
>>data in coordinates only where the data is also missing.
>>
>>I suppose that the pressure information is actually data in the raw obs
>>dataset. It would be legal to keep it in the file but not identify it as an
>>auxiliary coordinate variable (in the coordinates attribute). Then it would
>>be fine to having missing data in it. Would that be significantly less
>>convenient? Just a thought.
>>
>>Cheers
>>
>>Jonathan
>>_______________________________________________
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>>CF-metadata at cgd.ucar.edu
>>http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>
>
>
>
> ..............End of Message ...............................-->
>
>
>
>
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--
Dr. Richard P. Signell?? (508) 457-2229
USGS, 384 Woods Hole Rd.
Woods Hole, MA 02543-1598
Received on Tue Mar 27 2012 - 05:21:38 BST
