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[netCDFJava #XIR-445342]: Problem with netCDF-Java CoordinateAxis returning wrong values

Hi Tom,

I haven't totally tracked it down, but I've found something that does seem
to be different between the two. The bounding box that is computed using
netCDF-Java is incorrect for the NN file because the longitude spans the 
+/- 180, whereas this is not an issue with the NF files. It's possible that
this is leading to an error later on down the stack, but I haven't made it
that far yet. One thing that jumps out is that the longitude width of the 
bounding box is 349.9, but it is not considered a a global grid (that is, the
isGlobalLon() method on the GridCoordSys returns false). I'm wondering if
this ends up causing some problem on the IDV side. The variables actually
contain a projection called LatitudeLongitude, and that seems ok and is the
same as those found in the NF files. Again, still trying to track this down, but
I think I might be going in the right direction at this point...so, this is 
more of
an update than a fix, unfortunately.

John will be back in the office next week, so I'll speak with him them and
see if he has any ideas.



> Hi John & Sean --
> Now that the workshops are done, I'm hoping someone has had an
> opportunity to investigate why the IDV is not making a coordinate
> system when reading this file.  The user contacted me again this past
> week and is anxious to be able to use the tools for their work...so
> any help you can provide would be really appreciated.
> Thanks!
> Best wishes,
> tom
> On Wed, Jul 17, 2013 at 10:33 AM, Unidata netCDF Java Support
> <address@hidden> wrote:
> >> Hi John....
> >>
> >> Thanks for the explanation.  I understand things better now, and I
> >> conclude that the "only" issue remaining is that the IDV does not, for
> >> the "NN" file, create whatever is required so that the main 2D display
> >> can auto-set the projection to cover just the region enclosed by the
> >> data.    It also does not display correctly in the "world" projection
> >> (see attached, using the nightly build).  I can remap this into a
> >> South Pole conformal and it looks great, though...
> >
> > We will have to look at the IDV code, probably cant get to it until after 
> > the workshop.
> >
> > Long term, im starting to develop a new feature type class for satellite 
> > data, which could have different behavior than the grids. So if you have 
> > ideas how things could be handled better, id be interested.
> >
> >>
> >> McV has another (possibly related) issue in that the 2D display used
> >> for the scatter plots does not understand longitudes < -180
> >> apparently.  We will have to deal with that one, I guess.
> >
> > If you pass the lon value through a normalizer like 
> > LatLonPointImpl.lonNormal() you can adjust the range. If you dont need 
> > connectedness, maybe that is sufficent.
> >
> >
> >
> > John
> >
> >
> > Ticket Details
> > ===================
> > Ticket ID: XIR-445342
> > Department: Support netCDF Java
> > Priority: Urgent
> > Status: Open
> >
> --
> Tom Whittaker
> University of Wisconsin-Madison
> Space Science & Engineering Center (SSEC)
> Cooperative Institute for Meteorological Satellite Studies (CIMSS)
> 1225 W. Dayton Street
> Madison, WI  53706  USA
> ph: +1 608 262 2759

Ticket Details
Ticket ID: XIR-445342
Department: Support netCDF Java
Priority: Critical
Status: Open

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