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[netCDFJava #RIZ-451320]: why can't this be read as a grid

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  • Subject: [netCDFJava #RIZ-451320]: why can't this be read as a grid
  • Date: Fri, 16 May 2014 16:43:51 -0600
Hi Don,

The use of "grid_latitude" and "grid_longitude" standard names indicates a 
rotated pole grid mapping (defined in Appendix F: "Grid Mappings" section [1] 
of the CF spec). But lat and lon have the wrong units for a rotated pole grid 
(they should be "degrees") and a rotated pole grid mapping is not defined. 
(Here's the definition for "grid_latitude" [2] from the CF standard name table 
[3].)

Was the original dataset on a rotated pole grid?

Ethan

[1] http://cfconventions.org/1.6.html#appendix-grid-mappings

[2] "Latitude is positive northward; its units of degree_north (or equivalent) 
indicate this explicitly. In a latitude-longitude system defined with respect 
to a rotated North Pole, the standard name of grid_latitude should be used 
instead of latitude. Grid latitude is positive in the grid-northward direction, 
but its units should be plain degree."

[3] https://badc.nerc.ac.uk/help/formats/netcdf/cf-standard-name-table.html

Don Murray wrote:
> It doesn't like the standard_name for latitude and longitude (using ncml
> to remove them makes the grid readable).  I don't have the ability to
> remove them in the workflow, and this seems like a bug.
> 
> Don
> 
> On 5/16/14 3:35 PM, Unidata netCDF Java Support wrote:
> > There's confusion somewhere, ToolsUI is looking for a projection instead
> > of recognizing the lat lon coords.
> >
> > -Lansing
> >
> > On 5/16/2014 12:55 PM, Don Murray (NOAA Affiliate) wrote:
> >> New Ticket: why can't this be read as a grid
> >>
> >> Hi-
> >>
> >> I have a netCDF file that I created using the Climate Data Operators
> >> (CDO) package by subsetting a larger file.  The original file can be
> >> read into the IDV/ToolsUI, but the subset cannot (is not recognized as a
> >> grid).  I don't see anything obviously wrong with the file, except that
> >> maybe the CDM is getting confused by the use of x and y?
> >>
> >> Why doesn't the CDM recognize this as a grid?
> >>
> >> Don


Ticket Details
===================
Ticket ID: RIZ-451320
Department: Support netCDF Java
Priority: Normal
Status: Closed