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 <[email protected]
<mailto:[email protected]>> 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
[email protected] <mailto:[email protected]>
_______________________________________________
CF-metadata mailing list
[email protected]
http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
