[ncl-talk] plotting I J variables from the WRF out file

Mon May 11 19:19:02 MDT 2020

Hi,

I'm not surprised that no data is plotted. Again, you are treating the 1st
and 2nd columns of your zero_skipped file as lon/lat values. They look like
i,j indices to me, but conceivably could be lon/lats at 1 degree
boundaries. Regardless, they are values that are well outside the narrow
mpMin/Max/Lat/Lon values you've specified.

I don't understand the lat_lons.ncl script, and can't run it because I
don't have the WRF file. However, if I understand what you are trying to
do, I think you need to open that WRF file in test_1.ncl, like you did in
lat_lons.ncl, and after you've read in and converted the variables "lon"
"lat", pass those into wrf_user_ij_ll, and use the results of that to set
the sfXArray/sfYArray resources. For clarity, I personally would rename the
variables lat/lon as read in from the ascii file to something more like "i"
"j" or "row" "col"

Rick

On Mon, May 11, 2020 at 5:29 PM ali mughal via ncl-talk <ncl-talk at ucar.edu>
wrote:

> Dear NCL Team
>
> For the first question regarding modification to the code I did the
> attached changes (i.e. test1.ncl) though it shows the map where I intend to
> plot the data but still there is no data plotted. The I, j values in the
> csv I shared earlier and repeated here for convenience (zero_skipped.csv)
> correspond to the lat longs in the file (WRF_latlongs.xlsx).
>
> For the second question regarding the usage of wrf_user_ij_ll when I try
> to use this function like the way in the attached file (lat_lons.ncl) I get
> a segmentation fault (core dumped) message. However, if I don't use the
> script and copy these values directly into the ncl interface instead of
> submitting it in the form a script I get the values printed out. Please
> note that the I,j values printed here correspond to the same lat longs as
> in the file (WRF_lotlongs.xlsx).
>
> Regards
>
> On Tue, May 12, 2020 at 3:15 AM Dennis Shea <shea at ucar.edu> wrote:
>
>> Actually, it is not quite clearer what you are looking for:
>>
>> As indicated by Rick  *wrf_user_ij_to_ll*
>> <https://www.ncl.ucar.edu/Document/Functions/WRF_arw/wrf_user_ij_to_ll.shtml>
>>
>> other possibilities include the following very similar functions:
>>
>> *region_ind*
>> <https://www.ncl.ucar.edu/Document/Functions/Contributed/region_ind.shtml>
>> and  *getind_latlon2d*
>> <https://www.ncl.ucar.edu/Document/Functions/Contributed/getind_latlon2d.shtml>
>>
>> *You* must experiment. Please use print statements like *printVarSummary
>> *while debugging.
>> The output from *printVarSummary *is for you to look at to examine
>> variable type and shape, etc.
>>
>> On Sun, May 10, 2020 at 7:45 PM Rick Brownrigg via ncl-talk <
>> ncl-talk at ucar.edu> wrote:
>>
>>> Hi,
>>>
>>> Please do not reply directly back to me, but rather to the group as a
>>> whole -- they provide a broader pool of expertise to draw upon.
>>>
>>> I *think* wrf_user_ij_to_ll work() will do what you want, but it will
>>> likely require some experimentation. Liberal use of printVarSummary() is
>>> your best friend ;-)
>>>
>>> Rick
>>>
>>>
>>>
>>> On Sun, May 10, 2020 at 3:03 PM ali mughal <mughalali655 at gmail.com>
>>> wrote:
>>>
>>>> Dear Rick
>>>>
>>>> Thanks for the reply.
>>>>
>>>> In continuation to my previous email, I asked that in the shared the
>>>> first two columns represent I,j values of the WRF grid. If i have to
>>>> evaluate 2m air temperature on the same I,j values will wrf_user_ij_to_ll
>>>> work or do I need to use some other method.
>>>>
>>>> Regards
>>>>
>>>> On Sunday, May 10, 2020, Rick Brownrigg <brownrig at ucar.edu> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> There are at least two problems. One is that str_get_field() returns
>>>>> strings, and so "data" in the call to gsn_csm_contour_map() is a string,
>>>>> and this is the source of the error message. Try adding these 3 lines:
>>>>>
>>>>> lat := stringtofloat(lat)
>>>>> lon := stringtofloat(lon)
>>>>> data := stringtofloat(data)
>>>>>
>>>>> The other problem is that the min/max bounds are inappropriate for the
>>>>> data -- I get a blank plot. If I used the true min/max I get a mostly
>>>>> centered over Siberia:
>>>>>
>>>>> res at mpMinLatF = min(lat) ;-6.080154 ; range to zoom in on
>>>>> res at mpMaxLatF = max(lat) ;10.04061
>>>>> res at mpMinLonF = min(lon) ;95.908
>>>>> res at mpMaxLonF = max(lon) ;112.092
>>>>>
>>>>> Finally, the values for lat/lon in the file look suspect -- is this
>>>>> really a 1-degree grid? I might have guessed they are row/column values.
>>>>>
>>>>> Good luck,
>>>>> Rick
>>>>>
>>>>>
>>>>> On Sun, May 10, 2020 at 2:23 AM ali mughal via ncl-talk <
>>>>> ncl-talk at ucar.edu> wrote:
>>>>>
>>>>>> Dear Users
>>>>>>
>>>>>> I have csv file attached with the data available at specific grids of
>>>>>> the WRF outfile.Could any one help how to correct my attached code in NCL?
>>>>>>
>>>>>> When I try to run the code, I get the following error message
>>>>>>
>>>>>> (0)     This file has 4825 rows and 3 columns.
>>>>>> fatal:Argument type mismatch on argument (1) of (gsn_csm_contour_map)
>>>>>> can not coerce
>>>>>> fatal:["Execute.c":8578]:Execute: Error occurred at or near line 64
>>>>>> in file test_1.ncl
>>>>>>
>>>>>>
>>>>>> Later I want to use the same code to be modified to calculate 2m air
>>>>>> temperature at the same I J grids.
>>>>>>
>>>>>> Regards
>>>>>> _______________________________________________
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