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
compute_fromirr_bilinear_weigaddr
Interpolation
compute_fromirr_bilinear_weigaddr, olonin, olat, omsk, alonin, alat, amsk, weig, addr
Parameters
olonin
in
required
type: 2d array
longitude of the input data
olat
in
required
type: 2d array
latitude of the input data
omsk
in
required
type: 2d array or -1
land/sea mask of the input data
put -1 if input data are not masked
alonin
in
required
type: 2d array
longitude of the output data
alat
in
required
type: 2d array
latitude of the output data
amsk
in
required
type: 2d array or -1
land/sea mask of the output data
put -1 if output data are not masked
weig
out
type: 2d array
(see ADDR)
addr
out
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, jpia, jpja, /over)
Version history
Version
$Id: compute_fromirr_bilinear_weigaddr.pro 372 2008-08-08 12:31:53Z 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
- 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 weights are 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 same value as their closest neighbors
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