[gradsusr] Plotting a NEXRAD netCDF file

Sat Sep 21 09:24:14 EDT 2013

Thank you for doing this! I was going to play with both options myself, now
I don't have to. Did you have the set any specific options to obtain 'the
smallest data window possible' or does the grid dimension size option
(1600) automatically do this?

Thanks again,
Sytske

Sytske (seets-kah) Kimball
Professor of Meteorology
Director, South Alabama Mesonet
Dept. of Earth Sciences
University of South Alabama
Mobile, AL
phone (251) 460-7031
fax       (251) 460-7886
email   skimball at southalabama.edu <skimball at usouthal.edu>
web:   http://chiliweb.southalabama.edu/

On Fri, Sep 20, 2013 at 5:25 PM, Jeff Duda <jeffduda319 at gmail.com> wrote:

> I can confirm that works.  I see you have to select the output format in
> the WCT to be gridded netCDF 3 rather than native netCDF format, so you
> lose a little bit of fidelity by selecting the first option.  It also
> appears that you get more of that fidelity back if you select the maximum
> grid count (1600 in my version) and the smallest data window possible that
> fits the relevant data in.  This is shown by the attached images.  In the
> one titled KTLX_2328Z_reflectivity_only_3.gif, the data were created using
> the lowest grid cell size option (0.0075), whereas in
> reflectivity_1600_zoom.png, the data were created using the largest grid
> dimension size option (1600).
>
> Jeff
>
>
> On Fri, Sep 20, 2013 at 4:32 PM, Sytske Kimball <skimball at southalabama.edu
> > wrote:
>
>> It was level2 and I tried setting the Grid Cell Size in NOAA's WCT to a
>> finer resolution than the default value. That did the trick!!
>>
>> Sytske
>>
>>
>>
>> Sytske (seets-kah) Kimball
>> Professor of Meteorology
>> Director, South Alabama Mesonet
>> Dept. of Earth Sciences
>> University of South Alabama
>> Mobile, AL
>> phone (251) 460-7031
>> fax       (251) 460-7886
>> email   skimball at southalabama.edu <skimball at usouthal.edu>
>> web:   http://chiliweb.southalabama.edu/
>>
>>
>>
>> On Fri, Sep 20, 2013 at 3:39 PM, Jeff Duda <jeffduda319 at gmail.com> wrote:
>>
>>> Specifically which product did you convert?  Was it level 2 or level 3
>>> data?
>>>
>>> Jeff Duda
>>>
>>>
>>> On Fri, Sep 20, 2013 at 3:34 PM, Sytske Kimball <
>>> skimball at southalabama.edu> wrote:
>>>
>>>> Jennifer,
>>>>
>>>> I agree. Not sure how that happened. I used NOAA's Weather and Climate
>>>> Toolkit to convert the radar data to netCDF so maybe something went amiss
>>>> in that process.
>>>>
>>>> Thanks for your help,
>>>> Sytske
>>>>
>>>>
>>>> Sytske (seets-kah) Kimball
>>>> Professor of Meteorology
>>>> Director, South Alabama Mesonet
>>>> Dept. of Earth Sciences
>>>> University of South Alabama
>>>> Mobile, AL
>>>> phone (251) 460-7031
>>>> fax       (251) 460-7886
>>>> email   skimball at southalabama.edu <skimball at usouthal.edu>
>>>> web:   http://chiliweb.southalabama.edu/
>>>>
>>>>
>>>>
>>>> On Fri, Sep 20, 2013 at 3:25 PM, Jennifer Adams <jma at cola.iges.org>wrote:
>>>>
>>>>>
>>>>> On Sep 20, 2013, at 4:17 PM, Sytske Kimball wrote:
>>>>>
>>>>> Jennifer,
>>>>>
>>>>> Thanks for your response. Replies are added in below.
>>>>>
>>>>>
>>>>> On Fri, Sep 20, 2013 at 3:03 PM, Jennifer Adams <jma at cola.iges.org>wrote:
>>>>>
>>>>>>
>>>>>> On Sep 20, 2013, at 3:47 PM, Andrew Friedman wrote:
>>>>>>
>>>>>> Hi Sytske,
>>>>>>
>>>>>> In your script you have 2 plot settings right after each other:
>>>>>>
>>>>>> 'set gxout grfill'
>>>>>> 'set gxout shaded'
>>>>>>
>>>>>> I believe the second one overrides the first. Try commenting it out
>>>>>> to see what the grfill plot looks like.
>>>>>>
>>>>>> That's right -- grfill will give a better view of actual grid box
>>>>>> size. What does 'q ctlinfo' give you after you invoke sdfopen?
>>>>>>
>>>>>
>>>>> The plot with 'set gxout shaded' commented out, is attached - not very
>>>>> nice looking...….
>>>>>
>>>>> True, but that pixelated nature of the data explains why your shaded
>>>>> plot looked even worse.
>>>>>
>>>>>  'q ctlinfo' came back with the following:
>>>>>
>>>>> dset KMOB_V03_20091110_035730.nc
>>>>> title Nexrad 2 radar dataset  03:57:30 UTC  11/10/2009
>>>>> undef -999
>>>>> dtype netcdf
>>>>> xdef 800 linear -127.06 0.0776505
>>>>> ydef 490 linear 20.4756 0.0776505
>>>>>
>>>>> Which is about an 8km grid. I'm guessing the radar data is much higher
>>>>> resolution than that.
>>>>> --Jennifer
>>>>>
>>>>>
>>>>>
>>>>> zdef 1 linear 0 1
>>>>> tdef 1 linear 03:57Z10NOV2009 1mn
>>>>> vars 1
>>>>> Reflectivity=>reflectivity  0  t,y,x  Nexrad 2 radar dataset
>>>>> endvars
>>>>>
>>>>>
>>>>>
>>>>>>
>>>>>>
>>>>>> Also, you could try changing the shaded plot setting to the
>>>>>> higher-resoluttion algorithm:
>>>>>> 'set gxout shade2b'
>>>>>>
>>>>>> shade2b is not higher resolution -- it has more smaller polygons and
>>>>>> takes longer to render. shade2 and shade2b should look exactly the same.
>>>>>>
>>>>>
>>>>> 'set gxout shaded' and 'set gxout shade2' look the same.
>>>>>
>>>>> Sytske
>>>>>
>>>>>
>>>>>
>>>>>>
>>>>>>  --Jennifer
>>>>>>
>>>>>>
>>>>>> Andrew
>>>>>>
>>>>>> On Sep 20, 2013, at 12:23 PM, Sytske Kimball <
>>>>>> skimball at southalabama.edu> wrote:
>>>>>>
>>>>>> Dear GrADS users,
>>>>>>
>>>>>>
>>>>>> I (finally) managed to plot a NEXRAD radar reflectivity fil, in
>>>>>> netCDF format, using GrADS. The plot is attached (IdaRadar-test.png) as is
>>>>>> the original radar image for the same area, displayed using GRLevelII
>>>>>> (RadarLevel2.png). I can't figure out why the resolution on the GrADS image
>>>>>> is so much worse than on the original image. The script is also attached.
>>>>>>
>>>>>>
>>>>>> Any help would be much appreciated.
>>>>>>
>>>>>>
>>>>>> Thank you in advance,
>>>>>>
>>>>>> Sytske
>>>>>>
>>>>>>
>>>>>> Sytske (seets-kah) Kimball
>>>>>>
>>>>>> Professor of Meteorology
>>>>>>
>>>>>>  Director, South Alabama Mesonet
>>>>>>
>>>>>> Dept. of Earth Sciences
>>>>>>
>>>>>> University of South Alabama
>>>>>>
>>>>>> Mobile, AL
>>>>>>
>>>>>> phone (251) 460-7031
>>>>>>
>>>>>> fax       (251) 460-7886
>>>>>>
>>>>>> email   skimball at southalabama.edu
>>>>>>
>>>>>> web:   http://chiliweb.southalabama.edu/
>>>>>>
>>>>>> <RadarLevel2.png><IdaRadar-test.png><StationPlot+radar2.gs
>>>>>> >_______________________________________________
>>>>>>
>>>>>> gradsusr mailing list
>>>>>>
>>>>>> gradsusr at gradsusr.org
>>>>>>
>>>>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
>>>>>> gradsusr mailing list
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>>>>>>
>>>>>>
>>>>>>  --
>>>>>> Jennifer M. Adams
>>>>>> Center for Ocean-Land-Atmosphere Studies (COLA)
>>>>>> 111 Research Hall, Mail Stop 2B3
>>>>>> George Mason University
>>>>>> 4400 University Drive
>>>>>> Fairfax, VA 22030
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> _______________________________________________
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>>>>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>>>>
>>>>>>
>>>>> <IdaRadar-test2.png>_______________________________________________
>>>>> gradsusr mailing list
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>>>>>
>>>>>
>>>>>  --
>>>>> Jennifer M. Adams
>>>>> Center for Ocean-Land-Atmosphere Studies (COLA)
>>>>> 111 Research Hall, Mail Stop 2B3
>>>>> George Mason University
>>>>> 4400 University Drive
>>>>> Fairfax, VA 22030
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
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>>>>>
>>>>>
>>>>
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>>>>
>>>
>>>
>>> --
>>> Jeff Duda
>>> Graduate research assistant
>>> University of Oklahoma School of Meteorology
>>> Center for Analysis and Prediction of Storms
>>>
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>>>
>>
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>
>
> --
> Jeff Duda
> Graduate research assistant
> University of Oklahoma School of Meteorology
> Center for Analysis and Prediction of Storms
>
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