FORTRAN integer ezgdef, gdid gdid = ezgdef_fmem(ni, nj, grtyp, grref, ig1, ig2, ig3, ig4, ax, ay) integer ni, nj, ig1, ig2, ig3, ig4 character*1 grtyp, grref real ax(*), ay(*)

C gdid = c_ezgdef_fmem(int ni, int nj, char *grtyp, char *grref, int ig1ref, int ig2ref, int ig3ref, int ig4ref, float *ax, float *ay)

Routine description

This function is one of the most general entry point of the ezscint package to define a grid in conformance with the RPN standard file grid descriptors. It is applicable to both regular and irregular ('Y', 'Z') grids, although it is not very useful for regular grids. It also has a simpler front-end, ezqkdef. ezgdef_fmem insert a grid entry into the list of grids managed by the ezscint package. On completion, it returns "gdid", a token that can be used in later calls as a key to identify the grid, like the keys used in the RPN standard files. The values of the IG1-IG4 parameters will change depending on the context. If grtyp='Y' or 'Z', and grref='E', 'G', 'L', 'N', or 'S', the positional records are read from ax and ay, and the values of IG1 thru IG4 are those associated with the reference grid; they are normally obtained from a call to FSTPRM on the positional parameters ('^^', '>>'), and are referred to IG1REF thru IG4REF. If the grid type corresponds to a regular grid type (eg. 'A', 'G', 'N', etc.), then the parameters IG1 through IG4 are taken from an ordinary data record and grref, ax and ay are not used.

Description of parameters

ni, nj	horizontal dimensions of the grid
grtyp	type of grid ('A', 'B', 'E', 'G', 'L', 'N', 'S','Y', 'Z', '#', '!')
grref	Reference grid type ('E', 'G', 'L', 'N', 'S')
ig1ref, ig2ref, ig3ref, ig4ref	RPN standard file grid parameters of the positional parameters ('^^', '>>'), as returned by fstprm
ax, ay	positional axes. ax is mapped to the '>>' record, ay to '^^'. If grtyp == 'Z' or '#', the dimensions of ax=ni and ay=nj. If grtyp == 'Y', the dimensions of ax=ay=ni*nj.

The following functions can be invoked to get supplemental information about the grid.

gdgaxes	value of the positional records
gdll	lat-lon coordinates of the grid points
ezgprm	grid attributes of grid
ezgfstp or ezgxfstp	standard file attributes of the positional records

Sample FORTRAN code :

We want to interpolate data from any grid to a 400x200 Gaussian grid. 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 = ezgdef(nigem,njgem ,'Z','FILE', ig1, ig2, ig3, iun, unused, unused)

***   Define output grid and define grid set

      gdgauss = ezgdef(nigauss, njgauss, 'G', 0,0,0,0,unused, unused)

      ier = ezdefset(gdgauss, gdgem)

***   Now call ezsint

      ier = ezsint(zgauss, zgem)

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