[ncl-talk] accumulate data on grid

[Barry Lynn]

Hi Debasish:

You can easily turn your target grid into a 2D array.

https://www.ncl.ucar.edu/Document/Functions/Built-in/onedtond.shtml

On Sun, Oct 18, 2020 at 11:36 PM Dave Allured - NOAA Affiliate via ncl-talk
<ncl-talk at mailman.ucar.edu> wrote:

> Debasish,
>
> Sorry, you originally said "I have ... 2d lat, lon grid" and I
> misunderstood what that meant.  See other answers from Barry and Dennis.
> If you need more help, please show printVarSummary for your input variables
> x, lat, and lon, so we can be clear about what type of input data you have.
>
>
> On Sun, Oct 18, 2020 at 11:32 AM Paimazumder, Debasish <
> Debasish.Paimazumder at aig.com> wrote:
>
>> Dave- getind_latlon2d needs two-dimensional lat/lon while my output grid
>> 1-d lat/lon.
>> Interpolation from location to 1-d grid could be an option but we won’t
>> get the accumulation (sum) at the output grid.
>>
>> Best regards,
>> Dave
>>
>> On Oct 18, 2020, at 12:54 PM, Barry Lynn <barry.h.lynn at gmail.com> wrote:
>>
>> 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>*
>>>>>
>>>> _______________________________________________
> ncl-talk mailing list
> ncl-talk at mailman.ucar.edu
> List instructions, subscriber options, unsubscribe:
> https://mailman.ucar.edu/mailman/listinfo/ncl-talk



-- 
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

C.E.O, Weather It Is, LTD
Weather and Climate Focus
http://weather-it-is.com
Jerusalem, Israel
Local: 02 930 9525
Cell: 054 7 231 170
Int-IS: x972 2 930 9525
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.ucar.edu/pipermail/ncl-talk/attachments/20201019/fe89ac7e/attachment.html>