[ncl-talk] Error while handling multiple WRF output files

Mary Haley haley at ucar.edu
Fri Oct 6 13:16:20 MDT 2017 

Hello,

Thanks for providing clean scripts and explanations.

1. This warning is because when you use gsn_csm_contour_map to plot
curvilinear data, you must associate the lat/lon arrays with the data being
plotted. Otherwise, it does't know where on the map the data is supposed to
go.

If you looked at the wrf_gsn_1.ncl and wrf_gsn_2.ncl scripts, you'll see
they are both using special lat2d/lon2d attributes to accomplish this:

  hgt       = wrf_user_getvar(a,"HGT",it)    ; Terrain elevation
  hgt at lat2d = wrf_user_getvar(a,"XLAT",it)   ; latitude/longitude
  hgt at lon2d = wrf_user_getvar(a,"XLONG",it)  ; required for plotting

However, you would have to do this for every variable you plot.

Instead, you can set these two resources before any calls to
gsn_csm_contour_map:

res at sfXArray = lon
res at sfYArray = lat


​2. ​
I think the issue with cnConstFEnableFill
​ is that you are setting that resource *after* plots #0-5 have been
created.  You need to make sure this line:

    res at cnConstFEnableFill= True ; allow constant values (1=sig) to fill



​is *before* all of your gsn_csm_contour_map calls.

​3. In order to panel two sets of plots on the same page, you first need to
set:

pnlres at gsnFrame = False

so that the frame doesn't get advanced after each one. You will then need
to advance the frame yourself when done:

frame(wks)

The other issue with paneling two sets of plots, is that you need to make
sure they don't get drawn on top of each other. There are many examples on
our "Panels <http://www.ncl.ucar.edu/Applications/panel.shtml>" example
page that show how to do various configurations of plots and labelbars.
Here are some that might help:

http://www.ncl.ucar.edu/Applications/panel.shtml#ex12
http://www.ncl.ucar.edu/Applications/panel.shtml#ex22

The important thing is that you need to set gsnPanelRight / gsnPanelLeft to
control which part of the frame each set of plots is drawn in.  Since the
first set is 3 x 2 plots and the second set is 3 x 1 plots, this means the
3 x 2 plots should take up 2/3 of the width, and the 3 x 1 plots will take
up 1/3 of the width.

See attached script which uses dummy data.

--Mary




On Fri, Oct 6, 2017 at 2:04 AM, swati shewale <shewaleswati16 at gmail.com>
wrote:

> Hello Mary,
>
> As per your suggestion I went through the links provided by you. I will
> explain one by one the issues I came across while doing plot using inbuilt
> wrf function as well as gsn function separately. I have attached scripts
> along with plot. the kind of titles (as well as left and side string), I
> want is reflected in gsn plot which am unable to do in wrf plot. I have
> given suitable names to scripts as well as plot for your convenience. Hope
> you wont get confuse.
>
> In first script (1_plot_using_wrf_function)
> 1. after mentioning re at cnConstFEnableFill  = True, getting warning as
> warning:ContourPlotInitialize: scalar field is constant; no contour lines
> will appear; use cnConstFEnableFill to enable fill
>
> actually using wrf in built function gives nice plot but unable to make
> self explanatory (giving strings and titles) plot so thought of ploting
> using gsn function
>
> In second script (2_plot_using_gsn_function), issues are
>
> 1. even after mentioning lat/lon getting warning as follow
> (0)    check_for_y_lat_coord: Warning: Data either does not contain a
> valid latitude coordinate array or doesn't contain one at all.
> (0)    A valid latitude coordinate array should have a 'units' attribute
> equal to one of the following values:
> (0)        'degrees_north' 'degrees-north' 'degree_north' 'degrees north'
> 'degrees_N' 'Degrees_north' 'degree_N' 'degreeN' 'degreesN' 'deg north'
> (0)    check_for_lon_coord: Warning: Data either does not contain a valid
> longitude coordinate array or doesn't contain one at all.
> (0)    A valid longitude coordinate array should have a 'units' attribute
> equal to one of the following values:
> (0)        'degrees_east' 'degrees-east' 'degree_east' 'degrees east'
> 'degrees_E' 'Degrees_east' 'degree_E' 'degreeE' 'degreesE' 'deg east'
>
> 2. after mentioning re at cnConstFEnableFill  = True, getting warning as
> warning:ContourPlotInitialize: scalar field is constant; no contour lines
> will appear; use cnConstFEnableFill to enable fill
>
> 3. I want all 9 plots on single panel with scales vertical, instead I am
> getting it on two different pages
>
> I think, I have to manage or add more resources in pres1/pres2 such as (*vpXF
> <https://www.ncl.ucar.edu/Document/Graphics/Resources/vp.shtml#vpXF>* and *vpYF
> <https://www.ncl.ucar.edu/Document/Graphics/Resources/vp.shtml#vpYF>*) (*vpHeightF
> <https://www.ncl.ucar.edu/Document/Graphics/Resources/vp.shtml#vpHeightF>*
> and *vpWidthF
> <https://www.ncl.ucar.edu/Document/Graphics/Resources/vp.shtml#vpWidthF>*)
> , so that I may get 9 plots on single panel. If you know any link which
> resembles like the plot i want,Please let me know. side by I will again go
> through links given by you.
>
>
>
>
>
>
> On Sat, Sep 23, 2017 at 9:30 AM, swati shewale <shewaleswati16 at gmail.com>
> wrote:
>
>> Thank you so much Mary....surely I will go through the link provided by
>> you....If come across any problem, will let you know
>>
>> On Sat, Sep 23, 2017 at 12:36 AM, Mary Haley <haley at ucar.edu> wrote:
>>
>>> Please see this page:
>>>
>>> http://www.ncl.ucar.edu/Applications/wrfgsn.shtml
>>>
>>> and look at the first example (wrf_gsn_1.ncl and wrf_nogsn_1.ncl) and
>>> the second example (wrf_gsn_2.ncl).
>>>
>>> These show how to use gsn to plot data and it compares the plot with
>>> using WRF functions.
>>>
>>> In the wrf_gsn_1.ncl plot, you can see that the gsnLeft/RightString
>>> resources are being set automatically, because the data has a description
>>> and units attribute.
>>>
>>> Try this script as a start on your own data, and also look at
>>> wrf_gsn_2.ncl to see how to further customize your plot.
>>>
>>> If you are unable to get the plot to look as nice as you want, email
>>> ncl-talk at ucar.edu again with your new script and what you want it to
>>> look like, and we can help further.
>>>
>>> Good luck,
>>>
>>> --Mary
>>>
>>>
>>> On Fri, Sep 22, 2017 at 3:21 AM, swati shewale <shewaleswati16 at gmail.com
>>> > wrote:
>>>
>>>> Thank you Mary... its wrf file, I just renamed it for my convenience.
>>>> Actually I am able to plot it using wrf function but unable to put
>>>> left/right/centre strings, as those are related to gsn functions. so to
>>>> overcome the difficulty of left/right/centre, I thought to make a plot
>>>> using gsn functions injstead of wrf functions. but inbuilt wrf functions
>>>> gives nicer plots than gsn one.
>>>>
>>>> On Fri, Sep 22, 2017 at 3:48 AM, Mary Haley <haley at ucar.edu> wrote:
>>>>
>>>>> It's hard for somebody to simply look at a script to see if it's
>>>>> correct or not.  I do see some errors, but even if I correct the errors, I
>>>>> can't be sure it's 100% correct without having access to your data.
>>>>>
>>>>> The problems are:
>>>>>
>>>>> [1]
>>>>>
>>>>> Your data file is called "patna_data.nc". You are using wrf_xxxx
>>>>> functions to plot this data. Since WRF-ARW output files are normally called
>>>>> something like "wrfout_d02_2005-08-29_00:00:00", I can't be sure that
>>>>> you are actually plotting WRF-ARW data. You can only use wrf_xxx plotting
>>>>> functions on WRF-ARW data.
>>>>>
>>>>> [2]
>>>>>
>>>>> You have:
>>>>>
>>>>>  t   = a->T2(0:7,:,:)
>>>>>  ter = dim_avg_n( ter1, 0 )
>>>>>  ter = ter - 273
>>>>>
>>>>> I don't know what your objective, so I don't know if the above is
>>>>> correct.  However, you are calling "dim_avg_n" on "ter1" which doesn't
>>>>> exist.  Did you mean:
>>>>>
>>>>>  ter = dim_avg_n( t, 0 )
>>>>>
>>>>> The above will take an average of the first 8 times teps of your data,
>>>>> assuming that the leftmost dimension of T2 represents time.
>>>>>
>>>>> Further, you should use the _Wrap version of this function, so
>>>>> metadata is maintained:
>>>>>
>>>>>  ter = dim_avg_n_Wrap( t, 0 )
>>>>>
>>>>> [3]
>>>>>
>>>>> You have:
>>>>>
>>>>> ter = ter - 273
>>>>>
>>>>> Since you are changing the units, you should update the "units"
>>>>> attribute to something like this:
>>>>>
>>>>> ter at units = "degC"
>>>>>
>>>>>
>>>>> The rest of the script looks okay, but again, the wrf_contour and
>>>>> wrf_map_overlays procedures will only work if you are actually plotting
>>>>> WRF-ARW data.
>>>>>
>>>>> --Mary
>>>>>
>>>>>
>>>>>
>>>>> On Thu, Sep 7, 2017 at 10:02 PM, swati shewale <
>>>>> shewaleswati16 at gmail.com> wrote:
>>>>>
>>>>>> Thank you. I will try with your script. yesterday I tried it with
>>>>>> below script. Please have a look and let me know, whether it is correct or
>>>>>> not.
>>>>>>
>>>>>> On Fri, Sep 8, 2017 at 12:54 AM, Mary Haley <haley at ucar.edu> wrote:
>>>>>>
>>>>>>> If I understand you correctly, then you need to reshape your X array
>>>>>>> so that it is NTIM x 8 x NLAT x NLON, and then you can average across the
>>>>>>> second dimension from the left.
>>>>>>>
>>>>>>> I've attached a modified version of your script, which is UNTESTED.
>>>>>>> You may need to modify it to do the right thing with regard to copying over
>>>>>>> the required metadata.  I did this a little with copy_VarAtts, and
>>>>>>> copy_coords.
>>>>>>>
>>>>>>> --Mary
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Thu, Sep 7, 2017 at 3:42 AM, swati shewale <
>>>>>>> shewaleswati16 at gmail.com> wrote:
>>>>>>>
>>>>>>>> Hiii,
>>>>>>>> using ncrcat I have single file containing 24 time step (3hrly, 3
>>>>>>>> days). Now I want to plot temperature variable (average for each day,
>>>>>>>> spatial, panel plot). I am unable to take out time step for 1st day (0:7)
>>>>>>>> and then do average of it...then second day (8:15) ...likewise for third
>>>>>>>> day (16:23). I wrote a script, in that it takes average over all time
>>>>>>>> steps. what changes should I make so that I can get average over specific
>>>>>>>> time step? attached herewith script.
>>>>>>>> summary of variable temperature is as follow.
>>>>>>>>
>>>>>>>> Variable: X
>>>>>>>> Type: float
>>>>>>>> Total Size: 5658552 bytes
>>>>>>>>             1414638 values
>>>>>>>> Number of Dimensions: 3
>>>>>>>> Dimensions and sizes:    [Time | 23] x [south_north | 201] x
>>>>>>>> [west_east | 306]
>>>>>>>> Coordinates:
>>>>>>>> Number Of Attributes: 6
>>>>>>>>   FieldType :    104
>>>>>>>>   MemoryOrder :    XY
>>>>>>>>   description :    TEMP at 2 M
>>>>>>>>   units :    K
>>>>>>>>   stagger :
>>>>>>>>   coordinates :    XLONG XLAT XTIME
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On Thu, Sep 7, 2017 at 3:04 PM, swati shewale <
>>>>>>>> shewaleswati16 at gmail.com> wrote:
>>>>>>>>
>>>>>>>>> Thank you. I will try with it.
>>>>>>>>>
>>>>>>>>> On Wed, Sep 6, 2017 at 8:39 PM, Mary Haley <haley at ucar.edu> wrote:
>>>>>>>>>
>>>>>>>>>> The error message is telling you that there's something wrong
>>>>>>>>>> with argument 0 passed to wrf_contour.  Argument 0 refers to the first
>>>>>>>>>> argument in the list, which is "a(itime)" in this case.
>>>>>>>>>>
>>>>>>>>>> The issue is that when you use addfiles to open a series of
>>>>>>>>>> files, you need to use square brackets, [], to access a single file, and
>>>>>>>>>> not curved brackets, (). This is because addfiles returns a "List" object,
>>>>>>>>>> and lists in NCL need to be access with square brackets.
>>>>>>>>>>
>>>>>>>>>> You have:
>>>>>>>>>>
>>>>>>>>>>         contour = wrf_contour(a(itime),wks,t,t_res)
>>>>>>>>>>
>>>>>>>>>> and this should be:
>>>>>>>>>>
>>>>>>>>>>         contour = wrf_contour(a[itime],wks,t,t_res)
>>>>>>>>>>
>>>>>>>>>> --Mary
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On Mon, Sep 4, 2017 at 4:40 AM, swati shewale <
>>>>>>>>>> shewaleswati16 at gmail.com> wrote:
>>>>>>>>>>
>>>>>>>>>>> Hiiii
>>>>>>>>>>>
>>>>>>>>>>> I want to do panel plotting using WRF output. I have total 8
>>>>>>>>>>> files, each contains single time step (one day, 3 hrly datafiles so total 8
>>>>>>>>>>> files). out of eight times I want to plot 6 time step (panel plot) for
>>>>>>>>>>> variable slp and temperature.
>>>>>>>>>>>
>>>>>>>>>>> It shows below error.
>>>>>>>>>>>
>>>>>>>>>>> fatal:Argument type mismatch on argument (0) of (wrf_contour)
>>>>>>>>>>> can not coerce
>>>>>>>>>>> fatal:["Execute.c":8567]:Execute: Error occurred at or near
>>>>>>>>>>> line 44 in file temp.ncl
>>>>>>>>>>> (0)    Error: gsn_panel: all of the plots passed to gsn_panel
>>>>>>>>>>> appear to be invalid
>>>>>>>>>>>
>>>>>>>>>>>  Attached herewith script.
>>>>>>>>>>>
>>>>>>>>>>> Thank you in advance. Any help will be appreciated
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> _______________________________________________
>>>>>>>>>>> ncl-talk mailing list
>>>>>>>>>>> ncl-talk at ucar.edu
>>>>>>>>>>> List instructions, subscriber options, unsubscribe:
>>>>>>>>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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