In CMIP we require that? both missing_value and _FillValue be defined as
1.e20 for requested variables that occupy only a portion of the global
grid.? For bounds variables, I'll suggest that when needed, both
_FillValue and missing_value also be defined as 1.e20. That way software
that relies on either one will work.
My understanding of UGRID is that it provides for a much fuller
description of a grid than CF.? For CMIP, I think we can recommend UGRID
be used for non-standard grids, but I'm reluctant to require it.? Most
grids for most purposes I think can be adequately described with the
CF-mandated attributes.? Does anyone disagree?
thanks,
Karl
On 1/1/18 4:47 PM, Chris Barker wrote:
> On Wed, Dec 20, 2017 at 2:21 PM, Karl Taylor <taylor13 at llnl.gov
> <mailto:taylor13 at llnl.gov>> wrote:
>
>
> My sense is that no one violently opposes the use of missing_value
> to fill unused vertices for grid cells with fewer than the maximum
> number of vertices.
>
>
> I'm pretty sure this has been brought this up before (at least
> suggesting that UGRID be consulted )but UGRID uses _FillValue , rather
> than missing_value:
>
> http://ugrid-conventions.github.io/ugrid-conventions/#2d-flexible-mesh-mixed-triangles-quadrilaterals-etc-topology
>
> I have no recollection as to why that was chosen, but I encourage you
> not to do something different than an existing standard without good
> reason.
>
> For CMIP6 some models may need to define grids with a few cells
> having one less vertex than the majority.? I am (much too late in
> the process) writing down the data requirements for CMIP6 model
> output,
>
>
> Any reason CMIP shouldn't specify the? UGRID standard and be done with it?
>
> If there is something missing from the UGRID standard that is needed,
> please let us know, and ideally propose an addition.
>
> -CHB
>
>
>
> --
>
> Christopher Barker, Ph.D.
> Oceanographer
>
> Emergency Response Division
> NOAA/NOS/OR&R ? ? ? ? ? ?(206) 526-6959?? voice
> 7600 Sand Point Way NE ??(206) 526-6329?? fax
> Seattle, WA ?98115 ? ? ??(206) 526-6317?? main reception
>
> Chris.Barker at noaa.gov <mailto:Chris.Barker at noaa.gov>
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