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Interpolation/

fromreg.pro

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

topfromreg Interpolation

result = fromreg(method, datain[, lonin][, latin][, lonout], latout, WEIG=2d array, ADDR=2d array, NONORTHERNLINE=NONORTHERNLINE, NOSOUTHERNLINE=NOSOUTHERNLINE)

Return value

2D array the interpolated data

Parameters

method        in required type: string

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

datain        in required type: 2d array

a 2D array the input data to interpolate

lonin        in optional type: 1d or 2d array

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

latin        in optional type: 1d or 2d array

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

lonout        in optional type: 1d or 2d array

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

latout        in required type: 1d or 2d array

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

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. In that case, lonin, latin, lonout and latout are not necessary.

NONORTHERNLINE       

activate if you don't want to take into account the northern line of the input data when performing the interpolation.

NOSOUTHERNLINE       

activate if you don't want to take into account the southern line of the input data when performing the interpolation.

Examples

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: fromreg.pro 163 2006-08-29 12:59:46Z navarro $

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.

Statistics

McCabe cyclic 5
McCabe essential 1
McCabe modular design 1
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