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FORTRAN integer gdllsval, ier ier = gdllsval(gdid, zvals, zin, lat, lon, n) integer gdid, n real zvals(n), zin(*), lat(n), lon(n) |
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C int c_gdllsval(int gdid, float *zvals, float *zin, float *lat, float *lon, int n) |
Routine description
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gdllsval does a bi-dimensional scalar interpolation on the values contained in zin, themselves defined on grid gdid, at selected lat/lon points. Interpolated values are returned in zvals. |
Description of parameters
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gdid |
a valid grid identifier (returned by ezqkdef or ezgdef) that will be used as the source (input) grid. |
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zvals |
Output interpolated values. There is 1:1 relationship with zvals and lat/lon; that is, interpolated values at point lat(1), lon(1) is zvals(1). |
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zin |
Input (source) winds. zin is assumed to have the dimensions referred by gdid (the input grid). |
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lat |
Stream of latitude points |
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lon |
Stream of longitude points |
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n |
Number of points |
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Sample FORTRAN code :
We want to interpolate data from a GEM grid to selected lat-lon points. Assume necessary memory space has been allocated.
datev = -1
etiket = ' '
typvar = ' '
nomvar = 'GZ'
ip1 = 500
ip2 = 0
ip3 = -1
iun = 13
*** read fld info and data
key = FSTINF(iun, NI, NJ, NK, datev, etiket, ip1, ip2, ip3, typvar,
$ nomvar)
ier = FSTPRM(key, DATEO, DEET, NPAS, NI, NJ, NK, NBITS, DATYP, IP1,
$ IP2, IP3, TYPVAR, NOMVAR, ETIKET, GRTYP, IG1, IG2, IG3,
$ IG4, SWA, LNG, DLTF, UBC, EX1, EX2, EX3)
ier = FSTLUK(zgem, key, NI, NJ, NK)
*** Define input grid
gdgem = ezqkdef(ni, nj, 'Z', ig1, ig2, ig3, ig4, iun)
*** Define latlon values
lat(1) = 45.73
lon(1) = -73.75
lat(2) = 43.40
lon(2) = -79.38
lat(3) = 49.18
lon(3) = -123.18
*** Do scalar interpolation at the latlon points
ier = gdllsval(gdgem, zval, zgem, lat, lon, 3)
do i=1,3
print *, i,lat(i),lon(i),zval(i)
enddo
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