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Interpolation/

fromreg.pro

interpolate data from a "regular/rectangular grid" to any grid. 2 metods availables: bilinear and imoms3 A "regular/rectangular grid" is defined as a grid for which each lontitudes lines have the same latitude and each latitudes columns have the same longitude.

topfromreg interpolation

result = fromreg(method, datain, lonin, latin, lonout, latout, WEIG=WEIG, ADDR=ADDR, NONORTHERNLINE=NONORTHERNLINE, NOSOUTHERNLINE=NOSOUTHERNLINE)

Return value

2D array: the interpolated data

Parameters

method        in required

a string defining the interpolation method. must be 'bilinear' or 'imoms3'

datain        in required

a 2D array the input data to interpolate

lonin        in required

1D or 2D array defining the longitude of the input data

latin        in required

1D or 2D array defining the latitude of the input data

lonout        in required

1D or 2D array defining the longitude of the output data

latout        in required

1D or 2D array defining the latitude of the output data

Keywords

WEIG       

(see ADDR)

ADDR       

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 whithout computing again those 2 parameters. In that case, lonin, latin, lonout and latout are not necessary.

NONORTHERNLINE       

NOSOUTHERNLINE       

activate if you don't whant to take into account the northen/southern line of the input data when perfoming the interpolation.

Examples

dataout = fromreg(method, datain [, lonin, latin, lonout, latout]) IDL> topa = fromreg('bilinear', tncep, xncep, yncep, glamt, gphit) or IDL> t1opa = fromreg('bilinear', t1ncep, xncep, yncep, glamt, gphit, WEIG = a, ADDR = b) IDL> help, a, b IDL> t2opa = fromreg('bilinear', t2ncep, xncep, WEIG = a, ADDR = b)

Version history

Version

$Id$

History

November 2005: Sebastien Masson (smasson@lodyc.jussieu.fr)

Known issues

Restrictions

We supposed the data are located on a sphere, with a periodicity along the longitude.
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