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[IDV #JXK-429403]: In a netCDF file, the 2D field plots correctly, but the 3D field may not plot correctly dependent on sampling mode. [1465]



Hi Bob,

It looks like there were a few issues int he CDL file that were complicating
things. For example, the values used in the variable mask were not exactly
the same as the values used on the 300 hPa level of TAir. A bigger issue
is that the lat and lon variables, which were intended to be coordinate
variables, were 2D, and from what I can tell regarding CF, that is not 
allowed. 

I adjusted the CDL file, and things seem to be working correctly with the
new netCDF file that is generated. Please take a look and let me know if
everything seems ok on your end.

Cheers!

Sean

> Hi Sean -
> 
> Thanks for looking into this one.  I've attached the original file the
> user provided (test.cdl) and I just used ncgen to create a netCDF file
> from it.
> 
> Thanks -
> Bob
> 
> On 5/10/2013 9:14 AM, Unidata IDV Support wrote:
> > Greetings Bob,
> >
> > Would you mind sending the cdl file? I'll generate the netCDF file locally 
> > and
> > try to see what is going on in the 3D displays.
> >
> > Cheers!
> >
> > Sean
> >
> >> Hello -
> >>
> >> We have a user who has a netCDF file whose 3D data may not plot correctly 
> >> based on the sampling mode.  It appears that Weighted Average works better 
> >> than Nearest Neighbor, but both have their bugs.  If you want a sample 
> >> netCDF file as well as the *.cdl file that created it, please let us know. 
> >>  Any ideas of what may be going on?
> >>
> >> Thanks!
> >> Bob Carp
> >>
> >> ----==== Inquiry ====----
> >> 1465
> >>
> >> ----==== Summary ====----
> >> In a netCDF file, the 2D field plots correctly, but the 3D field may not 
> >> plot correctly dependent on sampling mode.
> >>
> >> ----==== Request ====----
> >> 2013-05-07 - Bob Carp
> >> Joleen has a netCDF file that she created from a *.cdl file using ncgen.  
> >> This file contains 2 arbitrary pressure levels, and random temperature 
> >> values that plot out at different lat/lon points (almost in the structure 
> >> of a 10 x 5 grid).  After adding this file, you can display a Value Plot 
> >> display of the 2D field fine with Weighted Average or Nearest Neighbor 
> >> sampling modes.  The problem comes when you try displaying the 3D data:
> >>
> >> - When using Weighted Average, select the 3D field, a pressure level, the 
> >> Value Plot display, and Create Display.  The data values displayed do not 
> >> match what is in the *.cdl file.  Some lines of numbers are repeated, and 
> >> some values don't plot at all.  In the Layer Controls (Displays tab), if 
> >> you change the level, and then change back to your original level, the 
> >> data displays much better (matches up with what is in the *.cdl file with 
> >> the exception of a little bit of interpolation).
> >>
> >> - When using Nearest Neighbor, select the 3D field, a pressure level, the 
> >> Value Plot display, and Create Display.  The data values displayed do not 
> >> match what is in the *.cdl file, and messing around in the Layer Controls 
> >> (Displays tab) does not correct the values.
> >>
> >> This was tested with both McV and IDV nightlies dated 05/07.
> >>
> >> 2013-05-06 - Bob Carp
> >> Joleen's initial email to the help desk:
> >> ----------------------------------------
> >> Bob was looking at this with me.  When I display 2D values, the data 
> >> displays monotonically, the same as it is written in the file.
> >>
> >> However, the 3D grids seem to use the wrong neighbor when displaying 
> >> (nearest neighbor is default for my setup).
> >>
> >> Check the input data object with
> >> a=selectData()
> >> print a
> >>
> >> 2013-05-06 - Bob Carp
> >> I added test.cdl and test.nc to /home/mcuser/inquiry-data/1456
> >>
> >> 2013-05-06 - Bob Carp
> >> Joleen has a netCDF file that has 2D and 3D data in it.  The 2D data 
> >> displays fine with the Value Plots display type.  When you display the 3D 
> >> data with the Value Plots display, not all of the data is displayed, and 
> >> some of it is displayed twice.  Doing a grid table display of the data 
> >> works fine (data does not repeat, and all data is listed.  Here is how the 
> >> 3D data looks in the .cdl file and in the Main Display window.
> >>
> >> In the .cdl file     In the Main Display window
> >> 0 1 2 3 4            0 1 2 3 4
> >> 10 11 12 13 14       20 21 22 24 25
> >> 20 21 22 24 25       30 31 32 33 34
> >> 30 31 32 33 34       30 31 32 33 40
> >> 35 36 37 38 39       40 41 42 43 44
> >> 40 41 42 43 44       40 41 42 43 44
> >> 45 46 47 48 49       50 51 52 53 54
> >> 50 51 52 53 54       50 51 52 53 54
> >> 60 61 62 63 64       70 71 72 73 74
> >> 70 71 72 73 74       70 71 72 73 74
> >>
> >> This has been tested in the 1.3b1 nightly from 05/06, 1.2, 1.01, and 1.0.  
> >> I also tested this with a recent IDV 4.0u2 nightly.  This was tested with 
> >> both Weighted Average and Nearest Neighbor sampling modes.
> >>
> >>
> >> ################################################################################
> >>
> >> http://dcdbs.ssec.wisc.edu/inquiry-v/index.php?inquiry=1465
> >>
> >>
> >
> > Ticket Details
> > ===================
> > Ticket ID: JXK-429403
> > Department: Support IDV
> > Priority: Normal
> > Status: Open
> >
> 
> 
> 


Ticket Details
===================
Ticket ID: JXK-429403
Department: Support IDV
Priority: Normal
Status: Open

Attachment: testFixed.cdl
Description: Binary data