[ncl-talk] accumulate data on grid

[Dave Allured - NOAA Affiliate]

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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