[ncl-talk] Getting location and dates of a point(s) that satisfy certain conditions

[Rashed Mahmood]

Hi Lyndz,
I think the problem is that one of your ind conditions results in missing
and hence this error message. You have to decide what to do when this sort
of situation arises. The attached adds an if statement that could be useful
in such scenarios but I am not sure if that is what you want.
Cheers,
Rashed


On Sat, Apr 17, 2021 at 6:30 AM Lyndz via ncl-talk <
ncl-talk at mailman.ucar.edu> wrote:

> Dear Sir Dennis and NCL-experts,
>
> I am getting this error:
>
> *fatal:Argument type mismatch on argument (0) of (ind_resolve) can not
> coerce*
>
>
>
> occurring near at the ncol line..
>
>
> Here's a sample file that I am using:
>
>
> https://www.dropbox.com/s/4nu4jh2v7uz6r45/mslp_jan16_2017.nc?dl=0
>
>
> Attached is the updated script.
>
>
>
> Any ideas on how to solve this?
>
>
>
> --Lyndz
>
>
> On Sat, Apr 17, 2021 at 2:52 AM Dennis Shea <shea at ucar.edu> wrote:
>
>> [1] The following has an error
>>
>>   dpdx_region=dpdx(:,{latS:latN},{lonL:lonR})
>>   *dpdx_region*=dpdy(:,{latS:latN},{lonL:lonR})   ;   should be *dpdy_region
>> <=====*
>>   px2py2_region=px2py2(:,{latS:latN},{lonL:lonR})
>>
>> [2] I don't see the need for your use of *dim_num_n*
>> <http://www.ncl.ucar.edu/Document/Functions/Built-in/dim_num_n.shtml>
>>
>> [4]  *ind_resolve*
>> <http://www.ncl.ucar.edu/Document/Functions/Built-in/ind_resolve.shtml>
>> is what you should use. Arrays must be made 1D.
>>       **** LOOK AT THE EXAMPLES****
>>
>>      dpdx_region_1d = *ndtooned*(dpdx_region)
>>      dpdy_region_1d = *ndtooned*(dpdy_region)
>>      px2py2_region_1d = *ndtooned*(px2py2_region)
>>
>> [5]    It is *highly* unlikely that the derivatives will be exactly 0.0
>> but ....
>>
>>   n_col  = ind_resolve(ind(dpdx_region_1d.eq. 0) .and. ind(dpdy_region_1d
>> .eq. 0) .and. ind(px2py2_region_1d.eq. 0) )
>>
>>   printVarSummary(n_col)
>>
>>
>> I'll stop there!
>>
>>
>>
>>
>>
>>
>> On Fri, Apr 16, 2021 at 2:38 AM Lyndz via ncl-talk <
>> ncl-talk at mailman.ucar.edu> wrote:
>>
>>> Dear NCL-experts,
>>>
>>> *[1] Details*
>>> I have three variables dpdx, dpdy, and px2py2 with the following
>>> dimensions and sizes:
>>> *Dimensions and sizes: [time | 124] x [lat | 73] x [lon | 144]*
>>> These variables were derived using spherical harmonics.
>>>
>>> *[2] Problem and what I have done so far*
>>>
>>> (a) I want to get the dates when any gridpoint in a specified domain
>>> satisfies the following conditions:
>>> dpdx = 0 *.and.* dpdy = 0 *.and. *px2py2 *.lt.* 0
>>>
>>> (b) get the coordinates of these points, if possible.
>>>
>>> I have the following lines in my script:
>>>
>>>   latS = 5.0
>>>
>>>   latN = 30.0
>>>
>>>   lonL = 120.0
>>>
>>>   lonR = 160.0
>>>
>>>   dpdx_region=dpdx(:,{latS:latN},{lonL:lonR})
>>>
>>>   dpdx_region=dpdy(:,{latS:latN},{lonL:lonR})
>>>
>>>   px2py2_region=px2py2(:,{latS:latN},{lonL:lonR})
>>>
>>> I am stuck here. I dont know what index I should use to get the dates
>>> and how to get their coordinates.
>>>
>>>   dpdx_thres  = dim_num_n((dpdx_region .eq. 0),(/1,2/))
>>>
>>>   dpdy_thres  = dim_num_n((dpdy_region .eq. 0),(/1,2/))
>>>
>>>   px2py2_thres  = dim_num_n((px2py2_region .lt. 0),(/1,2/))
>>>
>>>   n_thres  = ind(dpdx_thres .gt. 0 .and. dpdy_thres .gt. 0 .and.
>>> px2py2_thres .gt. 0 ) ;time indices but i'm not sure if this is correct!
>>>
>>>
>>>   print(n_thres)
>>>
>>>   print("=====")
>>>
>>>
>>>   if(ismissing(nt_thres(0))) then
>>>
>>>      print("++++++++++++++")
>>>
>>>      print(" NO values exceed threshold="+threshold)
>>>
>>>      print("++++++++++++++")
>>>
>>>   exit
>>>
>>>   end if
>>>
>>>
>>>
>>> I am attaching my script.
>>>
>>>
>>> I'll appreciate any help on this!
>>>
>>>
>>> Sincerely,
>>>
>>> *Lyndz*
>>>
>>>
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>>
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