[Paraview] troubles with netCDF reader ?
Hart, Cynthia Joyce - (cyndyb)
cyndyb at email.arizona.edu
Tue Aug 8 12:43:03 EDT 2017
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.lipsa at kitware.com>
Date: Friday, June 23, 2017 at 10:57 AM
To: Aashish Chaudhary <aashish.chaudhary at kitware.com>
Cc: "Hart, Cynthia Joyce - (cyndyb)" <cyndyb at email.arizona.edu>, "paraview at paraview.org" <paraview at 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.chaudhary at kitware.com<mailto:aashish.chaudhary at 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) <cyndyb at email.arizona.edu<mailto:cyndyb at 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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