triple2grid function for "nearest neighbor"?

Hi. I am trying to use the nearest neighbor technique to regrid TRMM
precipitation observations from a .25x.35 degree grid to a .5x.5 degree
grid.Is the the triple2grid function the recommended NCL function to use for
this purpose?

If so, I've tried using the technique in this example to regrid the data (
http://www.ncl.ucar.edu/Applications/Scripts/narr_3.ncl) , but I keep
running into this error:
fatal:triple2grid: The length of x and y must be the same as the rightmost
dimension of z

my command is this:
 rNEW(ii,:,:) = triple2grid(ndtooned(lon2d), ndtooned(lat2d), ndtooned(
r(ii,:,:)),lon,lat,False)

Does this mean that lon2d and lat2d must be the same size?
My command line code is below. Thank you for you help.
Erik

noble:TRMM3B42 enoble$ 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("TRMM_SOP3_0.25_res.nc","r")
ncl 6> r=a->precipitation
ncl 7> printVarSummary(r)

Variable: r
Type: float
Total Size: 71424000 bytes
            17856000 values
Number of Dimensions: 3
Dimensions and sizes: [time | 31] x [lat | 400] x [lon | 1440]
Coordinates:
            time: [1..31]
            lat: [-49.875..49.875]
            lon: [-179.875..179.875]
Number Of Attributes: 1
  _FillValue : -999
ncl 8> lat2d =a->lat
ncl 9> lon2d =a->lon
ncl 11> printVarSummary(lat2d)

Variable: lat2d
Type: float
Total Size: 1600 bytes
            400 values
Number of Dimensions: 1
Dimensions and sizes: [lat | 400]
Coordinates:
            lat: [-49.875..49.875]
Number Of Attributes: 0

ncl 19> print(" min="+min(lat2d)+" max="+max(lat2d))
(0) min=-49.875 max=49.875
ncl 20> print(" min="+min(lon2d)+" max="+max(lon2d))
(0) min=0.125 max=359.875

ncl 23> w = r(:,{7:18},{-20:-10})
ncl 24> NLAT = 200
ncl 25> MLON = 720
ncl 27> lat = ispan(0,NLAT-1,1)*0.50 - 49.875
ncl 28> lon = ispan(0,MLON-1,1)*0.50 - 179.875
ncl 29> lat!0 = "lat"
ncl 30> lat_at_units = "degrees_north"
ncl 31> lat&lat = lat
ncl 32> lon!0 = "lon"
ncl 33> lon_at_units = "degrees_east"
ncl 34> lon&lon = lon
ncl 35> rNEW = new ((/31,NLAT,MLON/),typeof(r),getFillValue(r))
ncl 36> rNEW!0 = "Time"
ncl 38> rNEW&Time = ispan(1,31,1)
ncl 39> rNEW!1 = "lat"
ncl 40> rNEW&lat = lat
ncl 41> rNEW!2 = "lon"
ncl 42> rNEW&lon = lon
ncl 47> do ii = 0,30
ncl 48> rNEW(ii,:,:) = triple2grid(ndtooned(lon2d), ndtooned(lat2d),
ndtooned( r(ii,:,:)),lon,lat,False)
ncl 49> end do
fatal:triple2grid: The length of x and y must be the same as the rightmost
dimension of z
fatal:Execute: Error occurred at or near line 48

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Received on Sat May 09 2009 - 10:00:58 MDT