[ncl-talk] accumulate data on grid
Dennis Shea
shea at ucar.edu
Tue Oct 20 16:35:50 MDT 2020
*bin_sum*
<https://www.ncl.ucar.edu/Document/Functions/Built-in/bin_sum.shtml>
returns the 'sums'. I am pretty sure it does what you want.
===
There is no need to average. What I sent was just extracted from the
exaample provided by the bin_sum documentation.
==
We can small the smoke. At times we can can have ashes from the fires
falling.
Stay Healthy
On Mon, Oct 19, 2020 at 3:56 PM Paimazumder, Debasish <
Debasish.Paimazumder at aig.com> wrote:
> Hi Dennis,
>
> Thanks for your response. Nice to hear from you and hope you are doing
> well and safe from recent wildfire in north boulder.
>
>
>
> I’m not sure that I understand the bin_sum function specially the second
> part (‘user must perform averaging’).
>
>
>
> For my case, dlon, dlat and d are from csv file and lat/lon from netcdf
> file. See blow their dimension. I would like create new variable at lat/lon
> grid by summing all d based on number of dlon, dlat within each of lat/lon
> grid.
>
>
>
> For example – if we have 50 dlat/dlon in one latXlon grid, then new
> variable in lat/lon grid = sum of d from all 50 dlat/dlon.
>
>
>
> With regards
>
> -Dave
>
>
>
> Variable: dlat
>
> Type: float
>
> Total Size: 1392092 bytes
>
> 348023 values
>
> Number of Dimensions: 1
>
> Dimensions and sizes: [348023]
>
> Coordinates:
>
> Number Of Attributes: 1
>
> _FillValue : 9.96921e+36
>
>
>
> Variable: dlon
>
> Type: float
>
> Total Size: 1392092 bytes
>
> 348023 values
>
> Number of Dimensions: 1
>
> Dimensions and sizes: [348023]
>
> Coordinates:
>
> Number Of Attributes: 1
>
> _FillValue : 9.96921e+36
>
>
>
> Variable: d
>
> Type: float
>
> Total Size: 1392092 bytes
>
> 348023 values
>
> Number of Dimensions: 1
>
> Dimensions and sizes: [348023]
>
> Coordinates:
>
> Number Of Attributes: 1
>
> _FillValue : 9.96921e+36
>
>
>
> *Output grid –*
>
> Variable: lat
>
> Type: float
>
> Total Size: 744 bytes
>
> 186 values
>
> Number of Dimensions: 1
>
> Dimensions and sizes: [lat | 186]
>
> Coordinates:
>
> lat: [-46.375..-0.125]
>
> Number Of Attributes: 4
>
> units : degree_north
>
> standard_name : latitude
>
> long_name : latitude
>
> bounds : lat_bnds
>
>
>
> Variable: lon
>
> Type: float
>
> Total Size: 964 bytes
>
> 241 values
>
> Number of Dimensions: 1
>
> Dimensions and sizes: [lon | 241]
>
> Coordinates:
>
> lon: [100.125..160.125]
>
> Number Of Attributes: 4
>
> units : degree_east
>
> standard_name : longitude
>
> long_name : longitude
>
> bounds : lon_bnds
>
> *From:* Dennis Shea <shea at ucar.edu>
> *Sent:* Sunday, October 18, 2020 2:25 PM
> *To:* Paimazumder, Debasish <Debasish.Paimazumder at aig.com>
> *Cc:* Barry Lynn <barry.h.lynn at gmail.com>; ncl-talk <ncl-talk at ucar.edu>
> *Subject:* [EXTERNAL] Re: [ncl-talk] accumulate data on grid
>
>
>
> *This message is from an external sender; be cautious with links and
> attachments.*
>
> Maybe the *"bin" examples
> <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ncl.ucar.edu_Applications_binning.shtml&d=DwMFaQ&c=kn4_INW_mBCDHV_xJEVJkg&r=fpudUXThXLQwAKQPDCnmVaSzm2dwE9OxcWi7MuJ0jbo&m=6F7M48QNHan0cjDH_KWLNBKvEM8Z4MLy0AVrfi5jQo8&s=esBoEZ_hYSHMOH9ETaF6M17fqzbclWD-fQGCOTkzhL0&e=>
> /* *functions*: * bin_sum
> <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ncl.ucar.edu_Document_Functions_Built-2Din_bin-5Fsum.shtml&d=DwMFaQ&c=kn4_INW_mBCDHV_xJEVJkg&r=fpudUXThXLQwAKQPDCnmVaSzm2dwE9OxcWi7MuJ0jbo&m=6F7M48QNHan0cjDH_KWLNBKvEM8Z4MLy0AVrfi5jQo8&s=xnFvaC2e9cElHG3_pafK084oquAu_2dJsejynvv5C-k&e=>*
> ,* bin_avg*
> <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ncl.ucar.edu_Document_Functions_Built-2Din_bin-5Favg.shtml&d=DwMFaQ&c=kn4_INW_mBCDHV_xJEVJkg&r=fpudUXThXLQwAKQPDCnmVaSzm2dwE9OxcWi7MuJ0jbo&m=6F7M48QNHan0cjDH_KWLNBKvEM8Z4MLy0AVrfi5jQo8&s=9NeB2QchXaY0pnTSSuyn5Qmj-7oUsC6EfwD4EXGQNYA&e=>
>
>
>
> Assuming the data are randomly located: d(npts), dlat(npts), dlon(npts)
>
> ***AND***
>
> the target grid is *RECTILINEAR* with grid locations/sizes: glon[mlon],
> glat[nlat]
>
>
>
> gbin = *new* <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ncl.ucar.edu_Document_Functions_Built-2Din_new.shtml&d=DwMFaQ&c=kn4_INW_mBCDHV_xJEVJkg&r=fpudUXThXLQwAKQPDCnmVaSzm2dwE9OxcWi7MuJ0jbo&m=6F7M48QNHan0cjDH_KWLNBKvEM8Z4MLy0AVrfi5jQo8&s=R3wqMSXgnUywYdf9AP9u9NrETGphvJvVf7GItjprpxI&e=> ( (/nlat,mlon/), float )
>
> gknt = *new* <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ncl.ucar.edu_Document_Functions_Built-2Din_new.shtml&d=DwMFaQ&c=kn4_INW_mBCDHV_xJEVJkg&r=fpudUXThXLQwAKQPDCnmVaSzm2dwE9OxcWi7MuJ0jbo&m=6F7M48QNHan0cjDH_KWLNBKvEM8Z4MLy0AVrfi5jQo8&s=R3wqMSXgnUywYdf9AP9u9NrETGphvJvVf7GItjprpxI&e=> ( (/nlat,mlon/), integer)
>
>
>
> gbin = 0.0 ; initialization
>
> gknt = 0
>
> *bin_sum*(gbin,gknt,glon,glat,dlon,dlat,d)
>
> ;*****************************************************************
>
> ; User must perform averaging
>
> ;*****************************************************************
>
> ; avoid division by 0
>
> gknt = *where* <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ncl.ucar.edu_Document_Functions_Built-2Din_where.shtml&d=DwMFaQ&c=kn4_INW_mBCDHV_xJEVJkg&r=fpudUXThXLQwAKQPDCnmVaSzm2dwE9OxcWi7MuJ0jbo&m=6F7M48QNHan0cjDH_KWLNBKvEM8Z4MLy0AVrfi5jQo8&s=4SbR5DjHbZc8obQVy_1-w-LH_brR9Bnv0Ixv8K46mA0&e=>(gknt.eq.0 , gknt at _FillValue, gknt)
>
>
>
> gbin = gbin/gknt
>
> gbin!0 = "lat"
>
> gbin!1 = "lon"
>
> gbin&lat = glat
>
> gbin&lon = lon
>
>
>
> *copy_VarCoords* <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ncl.ucar.edu_Document_Functions_Contributed_copy-5FVarCoords.shtml&d=DwMFaQ&c=kn4_INW_mBCDHV_xJEVJkg&r=fpudUXThXLQwAKQPDCnmVaSzm2dwE9OxcWi7MuJ0jbo&m=6F7M48QNHan0cjDH_KWLNBKvEM8Z4MLy0AVrfi5jQo8&s=H8H1S0QA3naQXQKhJSuJAT2QNQyKzwCTxbukEdlFtI8&e=>(gbin, gknt) ; copy coords
>
>
>
> if (*isfilevaratt* <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ncl.ucar.edu_Document_Functions_Built-2Din_isfilevaratt.shtml&d=DwMFaQ&c=kn4_INW_mBCDHV_xJEVJkg&r=fpudUXThXLQwAKQPDCnmVaSzm2dwE9OxcWi7MuJ0jbo&m=6F7M48QNHan0cjDH_KWLNBKvEM8Z4MLy0AVrfi5jQo8&s=pbnNxst9G_K0_R0bUV0jHQfBbWTAjBmkwShzIGuJjwE&e=>(f, vNam, "long_name")) then
>
> gbin at long_name = "BINNED: "+vNam
>
> gknt at long_name = "BINNED COUNT: "+vNam
>
> end if
>
>
>
> if (*isfilevaratt* <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ncl.ucar.edu_Document_Functions_Built-2Din_isfilevaratt.shtml&d=DwMFaQ&c=kn4_INW_mBCDHV_xJEVJkg&r=fpudUXThXLQwAKQPDCnmVaSzm2dwE9OxcWi7MuJ0jbo&m=6F7M48QNHan0cjDH_KWLNBKvEM8Z4MLy0AVrfi5jQo8&s=pbnNxst9G_K0_R0bUV0jHQfBbWTAjBmkwShzIGuJjwE&e=>(f, vNam, "units")) then
>
> gbin at units = f->$vNam$@units
>
> end if
>
>
>
> printVarSummary(gbin)
> printMinMax(gbin,1)
> print("=========")
> print("=========")
> printVarSummary(gknt)
> printMinMax(gbin,1)
>
> ====
>
> Note: If the target grid is *CURVILINEAR*: [ glat(nlat,mlon), glon(nlat,mlon], there is no NCL function to accomplish the task.
>
>
>
> On Sun, Oct 18, 2020 at 11:32 AM Paimazumder, Debasish via ncl-talk <
> ncl-talk at mailman.ucar.edu> 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:
>
>
>
> *This message is from an external sender; be cautious with links and
> attachments.*
>
> 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
>
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