Hello,

To make a long story short, this solution you used below, does not work well 
for the weather forecasting group here on my campus that I am working with.  Is 
there any possibility of obtaining the source code of the Paraview netCDF 
reader?  If I could edit that source code to accept the non- CF compliant WRF 
outputs, I could make use of Paraview in an automated script to create 
animations for our forecasters much, much more readily than manipulating netCDF 
file headers.  The data I’d sent to you was but a very small subset of the 
hundreds of netCDF files we’d need to change, every time we do a model run, and 
this is a process we’d like to actually automate daily.  I am unable to force 
the output to be compliant as it is created.  Can you help?

Sincerely,

Cynthia Hart


From: Dan Lipsa <dan.li...@kitware.com>
Date: Friday, June 23, 2017 at 10:57 AM
To: Aashish Chaudhary <aashish.chaudh...@kitware.com>
Cc: "Hart, Cynthia Joyce - (cyndyb)" <cyn...@email.arizona.edu>, 
"paraview@paraview.org" <paraview@paraview.org>
Subject: Re: [Paraview] troubles with netCDF reader ?

Cynthia,
It seems that the files you send us are not CF compliant.
The problem is that the Time dimension does not have a unit.


Here are some quotes from the CF Conventions document:
- The use of coordinate variables is required for all dimensions that 
correspond to one dimensional space or time coordinates.
- Variables representing time must always explicitly include the units 
attribute; there is no default value

So, to fix one of your files, I did:

1. ncdump ARAD4_test2.ncdf > ARAD4_test2_CF.txt

2. I added a new variable Time with the unit specified to the txt file.


float Time(Time) ;
Time:units = "minutes since 2016-07-29 12:00:00" ;

3.
I generated a new nc file:
ncgen ARAD4_test2_CF.txt -o  ARAD4_test2_CF.nc

This new file is read correctly by ParaView.

Best,
Dan



On Fri, Jun 16, 2017 at 6:31 PM, Aashish Chaudhary 
<aashish.chaudh...@kitware.com<mailto:aashish.chaudh...@kitware.com>> wrote:
Dear Cynthia,

Is there any chance that you can send me a sample dataset?

- Aashish

On Fri, Jun 16, 2017 at 6:15 PM Hart, Cynthia Joyce - (cyndyb) 
<cyn...@email.arizona.edu<mailto:cyn...@email.arizona.edu>> wrote:
Folks –

I am struggling with using the netCDF reader, with a bunch of timeseries of WRF 
data output (weather prediction modeling).  I am a visualizer, NOT a 
meteorologist, and so, my full understanding of the model’s output is shaky at 
best.  The researcher I am trying to assist is currently on vacation, and I’m 
trying to animate the output of his WRF model.

So!  I have been viewing some of the output using the built in reader in 
Paraview (the ‘generic and cf’ reader) and it works for some variables, not for 
others.  I am using NCO tools to extract some of the variables of interest into 
their own CDF file, to try and isolate the problem Paraview has, reading some 
variables.. but that doesn’t help.  I am particularly trying to read a variable 
for radar data, “REFL_10CM”.  Here is the relevant bit of the file header from 
ncdump, below:

netcdf ARAD4_test2 {
dimensions:
                Time = UNLIMITED ; // (1 currently)
                south_north = 393 ;
                west_east = 639 ;
                bottom_top = 37 ;
variables:
                float REFD_MAX(Time, south_north, west_east) ;
                                REFD_MAX:FieldType = 104 ;
                                REFD_MAX:MemoryOrder = "XY " ;
                                REFD_MAX:description = "MAX DERIVED RADAR REFL" 
;
                                REFD_MAX:units = "dbZ" ;
                                REFD_MAX:stagger = "" ;
                                REFD_MAX:coordinates = "XLONG XLAT XTIME" ;
                float REFL_10CM(Time, bottom_top, south_north, west_east) ;
                                REFL_10CM:FieldType = 104 ;
                                REFL_10CM:MemoryOrder = "XYZ" ;
                                REFL_10CM:description = "Radar reflectivity 
(lamda = 10 cm)" ;
                                REFL_10CM:units = "dBZ" ;
                                REFL_10CM:stagger = "" ;
                                REFL_10CM:coordinates = "XLONG XLAT XTIME" ;
                float XLAT(Time, south_north, west_east) ;
                                XLAT:FieldType = 104 ;
                                XLAT:MemoryOrder = "XY " ;
                                XLAT:description = "LATITUDE, SOUTH IS 
NEGATIVE" ;
                                XLAT:units = "degree_north" ;
                                XLAT:stagger = "" ;
                                XLAT:coordinates = "XLONG XLAT" ;
                float XLONG(Time, south_north, west_east) ;
                                XLONG:FieldType = 104 ;
                                XLONG:MemoryOrder = "XY " ;
                                XLONG:description = "LONGITUDE, WEST IS 
NEGATIVE" ;
                                XLONG:units = "degree_east" ;
                                XLONG:stagger = "" ;
                                XLONG:coordinates = "XLONG XLAT" ;
                float XTIME(Time) ;
                                XTIME:FieldType = 104 ;
                                XTIME:MemoryOrder = "0  " ;
                                XTIME:description = "minutes since 2016-07-29 
12:00:00" ;
                                XTIME:units = "minutes since 2016-07-29 
12:00:00" ;
                                XTIME:stagger = "" ;

Paraview complains that it cannot read a variable with more than three 
dimensions without time.  But there appears to ‘be’ time (I’m very unclear what 
“UNLIMITED” time , as seen in the header, refers to in this context).  Is there 
any way I can work around this?  Most frustrating.   I can actually read this 
variable into QGIS, but I’d rather use the strengths of Paraview to visualize 
this data.

Thanks in advance.


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