ezgdef

FORTRAN

 
integer ezgdef, gdid
gdid = ezgdef(ni, nj, grtyp, grref, ig1, ig2, ig3, ig4, ax, ay)
integer ni, nj, ig1, ig2, ig3, ig4
character*1 grtyp
character*4 grref
real ax(*), ay(*)

C

 
gdid = c_ezgdef(int ni, int nj, char *grtyp, char *grref, 
                 int ig1, int ig2, int ig3, int ig4, float *ax, float *ay)
 

            		
        

      
    

    
        
Routine description

      
    

      
        

           
            

          		
           
            
This function is 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. It also has a simpler
                front-end, ezqkdef.

              
              
ezgdef 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='FILE', the routine
                automatically loads the associated positional records ('^^') and
                (`>>`). The IG1 thru IG4 are those associated with a 'Z'
                grid; they are normally obtained from a call to FSTPRM on a
                regular data field ('GZ', 'TT', 'UU').

            
            
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.

          		
        

      
    

    
        
Description of parameters

      
    

      
        

           
            
ni, nj

          		
           
            
horizontal dimensions of the grid

          		
        

        

           
            
grtyp

          		
           
            
type of grid ('A', 'B', 'E', 'G', 'L', 'N',
                'S','Y', 'Z')

          		
        

        

           
            
grref

          		
           
            
Can be set to 'FILE' if the user wants the package
                to load the descriptors automatically. Any other reference grid
                type ('E', 'G', 'L', 'N', 'S') implies that the positional axes
                are to be read from "ax" and "ay". 

          		
        

        

          
                
ig1, ig2, ig3, ig4

                
or

              
            
ig1ref, ig2ref, ig3ref, ig4ref

          		
          
              
RPN standard file grid parameters. ig4 containts FORTRAN
                logical unit of the file containing the navigational records, if
                grtyp = 'Y' or 'Z'.

              
 

            
            
RPN standard file grid parameters of the
                positional parameters ('^^', '>>'), if the deformations
                axes, ax and ay, are given from memory.

          		
        

        

           
            
ax, ay

          		
           
            
positional axes. ax is mapped to the '>>'
                record, ay to '^^'. If grtyp == 'Z', 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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