Interpolation/
fromirr.pro
interpolate data from an irregular 2D grid to any 2D grid.
Only 1 method available = bilinear
fromirr
Interpolation
result = fromirr(method, datain[, lonin][, latin][, mskin][, lonout][, latout], mskout, WEIG=2d array, ADDR=2d array)
Return value
2D array the interpolated data
Parameters
method
in
required
type: string
a string defining the interpolation method. must be 'bilinear'
datain
in
required
type: 2d array
a 2D array the input data to interpolate
lonin
in
optional
type: 2d array
a 2D array defining the longitude of the input data
latin
in
optional
type: 2d array
a 2D array defining the latitude of the input data.
mskin
in
optional
type: 2d array or -1
a 2D array, the land-sea mask of the input data (1 on ocean, 0 on land)
put -1 if input data are not masked
lonout
in
optional
type: 1d or 2d array
1D or 2D array defining the longitude of the output data.
latout
in
optional
type: 1d or 2d array
1D or 2D array defining the latitude of the output data.
mskout
in
required
type: 2d array or -1
a 2D array, the land-sea mask of the output data (1 on ocean, 0 on land)
put -1 if output data are not masked
Keywords
WEIG
type: 2d array
(see ADDR)
ADDR
type: 2d array
2D arrays, weig and addr are the weight and addresses used to
perform the interpolation:
dataout = total(weig*datain[addr], 1)
dataout = reform(dataout, jpio, jpjo, /over)
Those keywords can be set to named variables (that are undefined or equal to 0) into which the
values will be copied when the current routine exits. Next, they can be used to perform
the interpolation without computing again those 2 parameters. This greatly
speed-up the interpolation! In that case, lonin, latin, lonout and latout are not necessary.
Examples
IDL> tncep = fromirr('bilinear', topa, glamt, gphit, tmask[*,*,0], lonout, latout, mskout)
or
IDL> t1ncep = fromirr('bilinear', topa, glamt, gphit, tmask[*,*,0], lonout, latout, mskout $
, WEIG = a, ADDR = b)
IDL> help, a, b
IDL> t2ncep = fromirr('bilinear', topa, WEIG = a, ADDR = b)
Version history
Version
$Id: fromirr.pro 202 2007-01-12 11:00:06Z smasson $
History
June 2006: Sebastien Masson (smasson@lodyc.jussieu.fr)
Known issues
Restrictions
We supposed the data are located on a sphere, with a periodicity along
the longitude.
Note that the input data can contain the same cells several times
(like ORCA grid near the north pole boundary)
Produced by IDLdoc 2.0.