Re: triple2grid: variable values are missing after using function?

Hi Bold,
triple2grid is meant to be used when you want to put randomly spaced
data (say, station data) onto a grid. As you are simply regridding from
one grid to another, I would use linint2_Wrap:
http://www.ncl.ucar.edu/Document/Functions/Contributed/linint2_Wrap.shtml

If the input field was global, didn't have any missing values, and was
not a field bounded by 0 (for example, precipitation), I would use one
of the spherical harmonic functions:
http://www.ncl.ucar.edu/Document/Functions/regrid.shtml
(All the f2* and g2* functions are spherical harmonic regridding functions.)
Good luck, and welcome to NCL.
Adam

B N wrote:
> Hi. NCL beginner here. I have spent an enormous amount of time going
> through beginner lessons to use NCL for my research. I like it.
> Unfortunately, I've encountered my first error that I can't figure
> out. I have searched previous posts
> and I don't see that others have encountered
> this with triple2grid. I don't see any.
>
> I use the triple2grid function to regrid 1/4 degree precipitation data
> (CMORPH) to a 1/2 degree grid (ncl 59>, below). After I regrid the
> data, my data is missing. I don't know why.
> ncl 62> printMinMax(rNEW,True)
> (0)
> (0) min=-999 max=-999
>
> Could I have some help with understanding this?
> Thank you for your time.
> -Bold Khan
>
> Fu School of Engineering,
> Earth and Environmental Engineering
> Columbia University
>
> mongol :CMORPH gkhan$ ncl
> Copyright (C) 1995-2009 - All Rights Reserved
> University Corporation for Atmospheric Research
> NCAR Command Language Version 5.1.0
> The use of this software is governed by a License Agreement.
> See http://www.ncl.ucar.edu/ for more details.
> ncl 0> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
> ncl 1> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
> ncl 2> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
> ncl 3> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"
> ncl 4> load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl"
> ncl 5> a = addfile("cmorph_SOP3_.25nc","r")
> ncl 6> rain_new = a->p_rate
> ncl 7> rain_new=rain_new(:,::-1,:)
> ncl 8> printVarSummary(rain_new)
>
>
> Variable: rain_new
> Type: float
> Total Size: 663552000 bytes
> 165888000 values
> Number of Dimensions: 3
> Dimensions and sizes: [time | 240] x [lat | 480] x [lon | 1440]
> Coordinates:
> time: [2.00609e+09..2.006093e+09]
> lat: [-59.875..59.875]
> lon: [0.125..359.875]
> Number Of Attributes: 3
> units : mm/hr
> long_name : CMORPH
> _FillValue : -9999
> ncl 9> printMinMax(rain_new,True)
> (0)
>
> (0) CMORPH: min=0 max=40.3708
> ncl 10> nlat = 480
> ncl 11> mlon = 1440
> ncl 12> time = ispan(1,dimsizes(rain_new(:,0,0)),1)
> ncl 13> lat = rain_new(0,:,0)
> ncl 14> lon = rain_new(0,0,:)
> ncl 15> lat!0 = "lat"
> ncl 16> lat&lat = lat
> ncl 17> lat_at_units = "degrees_north"
> ncl 18> lon!0 = "lon"
> ncl 19> lon&lon = lon
> ncl 20> lon_at_units = "degrees_east"
> ncl 21> ylat = lat
> ncl 22> xlon = lon
> ncl 23> ylat!0 = "Lat"
> ncl 24> xlon!0 = "Lon"
> ncl 25> lat2d = new((/480,1440/),float) ; CMORPH documentation
> ncl 26> lon2d = new((/480,1440/),float)
> ncl 27> lat2d!0 = "Lat"
> ncl 28> lat2d!1 = "Lon"
> ncl 29> lon2d!0 = "Lat"
> ncl 30> lon2d!1 = "Lon"
> ncl 31> lat2d_at_units = "degrees_north"
> ncl 32> lon2d_at_units = "degrees_east"
> ncl 33> ;=============; 2d grid coordinates should match the rain array.
> ncl 34> do i=0,479
> ncl 35> lon2d(i,:) = xlon(:)
> ncl 36> end do
> ncl 37> do i=0,1439
> ncl 38> lat2d(:,i) = ylat(:)
> ncl 39> end do
> ncl 40> NLAT = 240
> ncl 41> MLON = 720
> ncl 42> Lat = fspan(59.875,-59.875,240) ; lat for regridding to 0.5 degree
> ncl 43> Lon = fspan(0.125,359.875,720) ; lon for regridding to 0.5 degree
> ncl 44> Lat!0 = "lat"
> ncl 45> Lat_at_units = "degrees_north"
> ncl 46> Lat&lat = Lat
> ncl 47> Lon!0 = "lon"
> ncl 48> Lon_at_units = "degrees_east"
> ncl 49> Lon&lon = Lon
> ncl 50> rNEW = new
> ((/dimsizes(rain_new(:,0,0)),NLAT,MLON/),typeof(rain_new),getFillValue(rain_new))
> ;New rain array
> ncl 51> rNEW!0 = "time"
> ncl 52> rNEW&time = time
> ncl 53> rNEW!1 = "lat"
> ncl 54> rNEW&lat = Lat
> ncl 55> rNEW!2 = "lon"
> ncl 56> rNEW&lon = Lon
> ncl 57> print("Regridding with Triple2Grid Now.")
> (0) Regridding with Triple2Grid Now.
> ncl 58> do ii = 0,dimsizes(rNEW(:,0,0))-1 ;;;;;;Should be 0,239
> ncl 59> rNEW(ii,:,:) = triple2grid(ndtooned(lon2d), ndtooned(lat2d),
> ndtooned(rain_new(ii,:,:)),Lon,Lat,False)
> ncl 60> end do
> ncl 61> printVarSummary(rNEW)
> (0)
> (0) min=-999 max=-999
> ncl 63> exit
> _______________________________________________
> ncl-talk mailing list
> List instructions, subscriber options, unsubscribe:
> http://mailman.ucar.edu/mailman/listinfo/ncl-talk

-- 
--------------------------------------------------------------
Adam Phillips			             asphilli_at_ucar.edu
National Center for Atmospheric Research   tel: (303) 497-1726
ESSL/CGD/CAS                               fax: (303) 497-1333
P.O. Box 3000				
Boulder, CO 80307-3000	  http://www.cgd.ucar.edu/cas/asphilli
_______________________________________________
ncl-talk mailing list
List instructions, subscriber options, unsubscribe:
http://mailman.ucar.edu/mailman/listinfo/ncl-talk