[ncl-talk] accumulate data on grid

[Barry Lynn]

Right, that can be done.  Or, you can interpolate the data from the fine to
coarse grid.

I am not sure if the latter will conserve the averages like doing the
averaging in a loop.

On Sun, Oct 18, 2020 at 6:58 PM Dave Allured - NOAA Affiliate via ncl-talk <
ncl-talk at mailman.ucar.edu> wrote:

> Use the function *getind_latlon2d* to get the (i,j) grid point indices
> for the point data coordinates.  Then do a single loop over the point data
> to accumulate sums and counts on the output grid.
>
>
> On Sun, Oct 18, 2020 at 9:09 AM Paimazumder, Debasish via ncl-talk <
> ncl-talk at mailman.ucar.edu> wrote:
>
>> Hi Barry,
>> Thanks for your response. Actually I don’t have time dimension. I have
>> location level data (at high resolution).
>> For example, x(m) with lat(m) and lon (m) where m = 300k location
>>
>> My output grid is 32x32 km and I would like to do following
>> 1. Estimate the number of locations are in each 32x32 km grid
>> 2. Accumulate (sum) the x at each output grid.
>> For example- if I have 100 locations at one of the 32x32km grid, I will
>> sum all x from 100 locations and assign the sum to the output grid.
>>
>> Best regards,
>> Dave
>>
>> On Oct 18, 2020, at 3:50 AM, Barry Lynn <barry.h.lynn at gmail.com> wrote:
>>
>> Hi:
>>
>> If you have two grids of the same dimensions, but different times, you
>> can simply add them together.
>>
>> If you have grids of a different size, you can interpolate the data to
>> this grid, one grid at a time.
>>
>> See for example:
>>
>> https://www.ncl.ucar.edu/Applications/regrid.shtml
>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ncl.ucar.edu_Applications_regrid.shtml&d=DwMFaQ&c=kn4_INW_mBCDHV_xJEVJkg&r=fpudUXThXLQwAKQPDCnmVaSzm2dwE9OxcWi7MuJ0jbo&m=IaFm8AuXStzIPZXMbIRmp6fjt5zy74eAUUQzoQb5pBc&s=tUIMDu-yehcnE2-mHTaX2NhZiAg5eBHJsqf3e1Bmbl8&e=>
>>
>> This may also help.
>>
>> https://www.ncl.ucar.edu/Document/Functions/Built-in/dim_sum_n.shtml
>> <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ncl.ucar.edu_Document_Functions_Built-2Din_dim-5Fsum-5Fn.shtml&d=DwMFaQ&c=kn4_INW_mBCDHV_xJEVJkg&r=fpudUXThXLQwAKQPDCnmVaSzm2dwE9OxcWi7MuJ0jbo&m=IaFm8AuXStzIPZXMbIRmp6fjt5zy74eAUUQzoQb5pBc&s=4tdKFBxFBOUpMYFj95WyO8MUdUcYRniTWsJIvCCbhAE&e=>
>>
>> On Sun, Oct 18, 2020 at 7:59 AM Paimazumder, Debasish via ncl-talk <
>> ncl-talk at mailman.ucar.edu> wrote:
>>
>>> Hi NCL users
>>>
>>> I have location level data and 2d lat, lon grid and I’m trying to
>>> accumulate the data on  2d lat, lon grid.
>>>
>>>
>>>
>>> For example
>>>
>>> Input - x (n) with lat(n), lon(n)
>>>
>>> Output grid - lat(i)xlon(j)
>>>
>>> I’m trying to estimate number of location within each grid and
>>> accumulate x at each grid.
>>>
>>> Is there any function in NCL that will solve this problem?
>>>
>>>
>>>
>>> With regards
>>>
>>> -Debasish
>>>
>>>
>>>
>>> *Debasish PaiMazumder, PhD |*Tel +1 215 255 6052
>>> <%2B1%20215%20255%206371> | Cell +1 267 449 5226
>>> <%2B1%20718%20913%206946> |*Debasish.Paimazumder at aig.com
>>> <Debasish.Paimazumder at aig.com>*
>>>
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-- 
Barry H. Lynn, Ph.D
Senior Associate Scientist, Lecturer,
The Institute of the Earth Science,
The Hebrew University of Jerusalem,
Givat Ram, Jerusalem 91904, Israel
Tel: 972 547 231 170
Fax: (972)-25662581

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