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Interpolation/

compute_fromirr_bilinear_weigaddr.pro

compute the weight and address needed to interpolate data from an "irregular 2D grid" (defined as a grid made of quadrilateral cells) to any grid using the bilinear method

topcompute_fromirr_bilinear_weigaddr interpolation

compute_fromirr_bilinear_weigaddr, olonin, olat, omsk, alonin, alat, amsk, weig, addr

Parameters

olonin        in required

longitudeof the input data

olat        in required

latitude of the input data

omsk        in required

land/se mask of the input data

alonin        in required

longitude of the output data

alat        in required

latitude of the output data

amsk        in required

land/sea mask of the output data

weig        out

addr        out

2D arrays, weig and addr are the weight and addresses used to perform the interpolation: dataout = total(weig*datain[addr], 1) dataout = reform(dataout, jpia, jpja, /over)

Version history

Version

$Id: compute_fromirr_bilinear_weigaddr.pro 118 2006-06-27 15:47:06Z pinsard $

History

June 2006: Sebastien Masson (smasson@lodyc.jussieu.fr)

Known issues

Restrictions

- the input grid must be an "irregular 2D grid", defined as a grid made of quadrilateral cells which corners positions are defined with olonin and olat - We supposed the data are located on a sphere, with a periodicity along the longitude - to perform the bilinear interpolation within quadrilateral cells, we first morph the cell into a square cell and then compute the bilinear interpolation. - if some corners of the cell are land points, their weight is set to 0 and the weight is redistributed on the remaining "water" corners - points located out of the southern and northern boundaries or in cells containing only land points are set the the same value as their closest neighbor l;
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