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[Support #YZT-862981]: AMV NetCDF files read in with the incorrect time in McV 1.6, but it worked in 1.5. [2405]
- Subject: [Support #YZT-862981]: AMV NetCDF files read in with the incorrect time in McV 1.6, but it worked in 1.5. [2405]
- Date: Wed, 07 Sep 2016 16:38:45 -0600
> Hello -
>
> We have a few AMV (Atmospheric Motion Vector) point NetCDF files that worked
> correctly in McV 1.5 and IDV 5.0, but don't work correctly in versions more
> recent than those. See the Request of this inquiry for more information as
> well as the location of the files. We have set Tommy J as the POC at SSEC.
> I've run this by the NetCDF/java group and they pointed me to you to see if
> you had any ideas on what might be happening on the IDV side.
>
> Any thoughts?
>
> Thanks -
> Bob Carp
>
Bob,
Quick answer is that the latest netCDF-Java library has stricter requirement of
the dataset to be in better CF compliance comparing to the earlier version. I
will download a sample and find out what need to be changed.
Yuan
> ----==== Inquiry ====----
> 2405
>
> ----==== Summary ====----
> AMV NetCDF files read in with the incorrect time in McV 1.6, but it worked in
> 1.5.
>
> ----==== Request ====----
> 2016-09-07 - Bob Carp
> There are currently three files in ftp://ftp.ssec.wisc.edu/pub/incoming:
>
> amv.HIMAWARI-8.2015313.0010.ch_14.nc
> amv.Meteosat-10.2015304.1200.ch_14.nc
> amv.MTSAT-2.2014251.1114.ch_14.nc
>
> In the IDV 5.0 and McIDAS-V 1.5, these files can all be read in as a
> 'netCDF/GEMPAK Point Data files' data type. When the 'Point Data' field is
> displayed with the Point Data display type, two things happen:
> 1. The data displays with the correct timestamp
> 2. All of the vectors display in the same timestep
>
> In any IDV/McV versions more recent than the version listed above, two things
> happen:
> 1. The data displays with the incorrect timestamp (1969-21-31 or 1970-01-01)
> 2. All of the vectors want to display in their own timestep (you can 'fix'
> this by adjusting the time binning of the data source)
>
> I checked with the NetCDF/java group at Unidata and here was their response:
> As far as I can tell, toolsUI 4.3 vs 4.6 does not treats these files in the
> same way. I know the IDV team, specifically Julien, has done some work in the
> IDV to improve the handling of Point Data. It's possible that there is a bug
> there, or maybe even in the way the PointFeature API from netCDF-Java is
> being used. It also might be a limitation of the PointFeeature API, which
> treats point data as a stream. Have you contacted the IDV group to see if
> they are able to see what is going on with these files?
>
> Any thoughts? The files mentioned above should remain on ftp for a week
> (through 9/14). If anyone needs access to them after that date let me know
> and I can re-post them.
>
> 2016-08-31 - Bob Carp
> The summary of this inquiry was:
> Meteosat AMV NetCDF file reads in with the incorrect time in McV 1.6, works
> in 1.5.
>
> I'm changing it to:
> AMV NetCDF files read in with the incorrect time in McV 1.6, but it worked in
> 1.5.
>
> This is because other AMV files have the same problem, such as Himawari and
> MTSAT. For sample data, see /home/mcuser/inquiry-data/2417/*.
>
> 2016-08-13 - Bob Carp
> Load the amv.Meteosat-10.2015304.1200.ch_14.nc file as a NetCDF/GEMPAK Point
> Data Source. Through the Properties window of the data source, change the
> time binning to 1 hour. This prevents having individual timesteps for each
> data point. Note that this is a change from 1.5, where in 1.5 you didn't
> need to change the time binning for things to display in one tilmestep.
> However, each point really does have its own time, so this probably isn't a
> big deal.
>
> The main problem is that in 1.6 the timestamp (macro and in the Time
> Animation Widget) reads as 1969-21-31 23:58 (with time binning of 1 hr). In
> McV 1.5 the timestamp is read as 2015-10-31 12:00:00Z which matches the time
> in the filename.
>
>
> ################################################################################
>
> http://mcidas.ssec.wisc.edu/inquiry-v/index.php?inquiry=2405
>
>
Ticket Details
===================
Ticket ID: YZT-862981
Department: Support IDV
Priority: Normal
Status: Open
===================
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