[ncl-talk] Creating histogram based on the number of gridpoints

[Lyndz]

Dear Sir Adam and NCL experts.

I found an example of what I am looking for. Please see the attached gif
file for this.

The attached image shows number of gridpoints (y-axis) versus rainfall
(x-axis).
This came from
http://www.cgd.ucar.edu/cms/cchen/VDIAG_hybrid_v5_rel04_BC5_ne120_t12_pop62/daily.html

I'll appreciate any help you can provide.

Sincerely,
Lyndz

On Tue, Sep 10, 2019 at 2:29 AM Lyndz <olagueralyndonmark429 at gmail.com>
wrote:

> Dear Sir Adam,
>
> Thank you for the information.
> I apologize for the unclear question.
>
> Is there a way to plot a histogram this way:
> x-axis: bin of gridpoints (say in my previous email, there are 300
> gridpoints within rain_region. Then I have to bin this by 5)
> y-axis: frequency of rainfall occurrence above 0 mm/day.
>
> Thank you so much for the help.
>
> Sincerely,
> Lyndz
>
> On Tue, Sep 10, 2019 at 2:11 AM Adam Phillips <asphilli at ucar.edu> wrote:
>
>> Hi Lyndz,
>> Perhaps I am not understanding what you are wanting to do, but I think
>> gsn_histogram will do exactly what you need, regardless of whether you are
>> counting up the number of grid points or values in a timeseries that fall
>> in each bin.  You would pass ndtooned(rain_region) into gsn_histogram, and
>> it doesn't matter whether you pass every time step individually or all
>> timesteps at once.
>> Adam
>>
>> On Mon, Sep 9, 2019 at 12:38 AM Lyndz via ncl-talk <ncl-talk at ucar.edu>
>> wrote:
>>
>>> Dear NCL-experts,
>>>
>>> *[Details]*
>>>
>>> I am using the aphrodite rainfall data set, which I uploaded in my
>>> dropbox folder:
>>> https://www.dropbox.com/s/lbkjlqgq9era5c7/APHRO_AMJ_1979-2015.nc?dl=0
>>>
>>>
>>> I would like to count the number of grid points over a specified region
>>> with rainfall in the following intervals(mm/day): 0-2,
>>> 2-4,4-6,6-8,8-10,10-12,12-14,14-16,16-18,18-20,20-22,22-24,24-26,26-28,28-30.
>>> Then, create a histogram.
>>>
>>>   f1  = addfile("APHRO_AMJ_1979-2015.nc","r")
>>>
>>>
>>>
>>> *  latS = 12.5  latN = 20.0  lonL = 120.0  lonR = 122.5*
>>>   prec = f1->precip(:,:,:)
>>>   rain_region=prec(:,{latS:latN},{lonL:lonR})   ;select subregion
>>>
>>> This is almost similar to this example
>>> https://www.ncl.ucar.edu/Applications/Scripts/Katrina_circle_hist.ncl
>>> But I am binning the number of grid points.
>>>
>>> Any suggestions on how to do this in NCL?
>>>
>>> I'll appreciate any guidance.
>>>
>>> Sincerely,
>>> Lyndz
>>> _______________________________________________
>>> ncl-talk mailing list
>>> ncl-talk at ucar.edu
>>> List instructions, subscriber options, unsubscribe:
>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>
>>
>>
>> --
>> Adam Phillips
>> Associate Scientist,  Climate and Global Dynamics Laboratory, NCAR
>> www.cgd.ucar.edu/staff/asphilli/   303-497-1726
>>
>> <http://www.cgd.ucar.edu/staff/asphilli>
>>
>
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