NAME

       ncflint - netCDF File Interpolator

SYNTAX

       ncflint [-3] [-4] [-5] [-6] [-7] [-A] [--bfr sz_byt][-C][-c] [--cmp cmp_sng] [--cnk_byt sz_byt][--cnk_csh
       sz_byt][--cnk_dmn  nm,sz_lmn]  [--cnk_map  map]  [--cnk_min sz_byt] [--cnk_plc plc] [--cnk_scl sz_lmn][-D
       dbg_lvl] [-d dim,[ min][,[ max]]] [-F] [--fl_fmt=fmt] [--fix_rec_crd] [-G gpe_dsc] [-g grp[,...]]  [--glb
       att_name= att_val]] [-H] [-h] [--hdf] [--hdr_pad sz_byt][--hpss_try] [-i var,val3][-L  dfl_lvl][-l  path]
       [--msa]  [-N] [--no_cll_msr] [--no_frm_trm] [--no_tmp_fl] [-O] [-p path] [--ppc var1[, var2[,...]]= prc]]
       [-R] [-r] [--ram_all] [-t thr_nbr] [--uio] [--unn] [-v var[,...]]  [-w wgt[, wgt2]] [-X box]  [-x]  file1
       file2 file3

DESCRIPTION

       ncflint  creates an output file that is a linear combination of the input files.  This linear combination
       can be a weighted average, a normalized weighted  average,  or  an  interpolation  of  the  input  files.
       Coordinate variables are not acted upon in any case, they are simply copied from file_1.
        There are two conceptually distinct methods of using ncflint.  The first method is to specify the weight
       each  input  file  is  to  have  in the output file.  In this method, the value val3 of a variable in the
       output file file_3 is determined from its values val1 and val2  in  the  two  input  files  according  to
       wgt1*val1+wgt2*val2

       Here  at least wgt1, and, optionally, wgt2, are specified on the command line with the -w (or --weight or
       --wgt_var ) switch.  If only wgt1 is specified then wgt2 is automatically computed as wgt2=1-wgt1.   Note
       that  weights larger than 1 are allowed.  Thus it is possible to specify wgt1=2 and wgt2=-3.  One can use
       this functionality to multiply all the values in a given file by a constant.

       The second method of using ncflint is to specify the interpolation option with -i (or with the  --ntp  or
       --interpolate long options). This is really the inverse of the first method in the following sense.  When
       the  user  specifies the weights directly, ncflint has no work to do besides multiplying the input values
       by their respective weights and adding the results together to produce the output values.   This  assumes
       it  is  the  weights that are known a priori.  In another class of cases it is the "arrival value" (i.e.,
       val3 ) of a particular variable var that is known a priori.  In this case, the implied weights can always
       be inferred by examining the values of var in the input files.  This  results  in  one  equation  in  two
       unknowns, wgt1 and wgt2: val3=wgt1*val1+wgt2*val2.

       Unique  determination  of the weights requires imposing the additional constraint of normalization on the
       weights: wgt1+wgt2=1.  Thus, to use the interpolation option, the user specifies var and val3 with the -i
       option.  ncflint will compute wgt1 and wgt2, and use these weights  on  all  variables  to  generate  the
       output  file.   Although  var  may  have any number of dimensions in the input files, it must represent a
       single, scalar value.  Thus any dimensions associated with var must be "degenerate", i.e., of size one.

        If neither -i nor -w is specified on the command line, ncflint defaults to  weighting  each  input  file
       equally  in  the  output  file.   This  is  equivalent to specifying -w 0.5 or -w 0.5,0.5.  Attempting to
       specify both -i and -w methods in the same command is an error.

       ncflint is programmed not to interpolate variables  of  type  NC_CHAR  and  NC_BYTE.   This  behavior  is
       hardcoded.

AUTHOR

       NCO manual pages written by Charlie Zender and originally formatted by Brian Mays.

REPORTING BUGS

       Report bugs to <http://sf.net/bugs/?group_id=3331>.

COPYRIGHT

       Copyright © 1995-present Charlie Zender
       This  is  free  software;  see  the  source  for  copying conditions.  There is NO warranty; not even for
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

       The full documentation for NCO is maintained as a Texinfo manual called the NCO Users Guide.  Because NCO
       is mathematical in nature, the documentation includes TeX-intensive portions not viewable  on  character-
       based  displays.   Hence  the only complete and authoritative versions of the NCO Users Guide are the PDF
       (recommended), DVI, and Postscript versions at <http://nco.sf.net/nco.pdf>,  <http://nco.sf.net/nco.dvi>,
       and    <http://nco.sf.net/nco.ps>,    respectively.    HTML   and   XML   versions   are   available   at
       <http://nco.sf.net/nco.html> and <http://nco.sf.net/nco.xml>, respectively.

       If the info and NCO programs are properly installed at your site, the command

              info nco

       should give you access to the complete manual, except for the TeX-intensive portions.

       ncap2(1), ncatted(1), ncbo(1), ncclimo(1), nces(1), ncecat(1), ncflint(1), ncz2psx(1),  ncks(1),  nco(1),
       ncpdq(1), ncra(1), ncrcat(1), ncremap(1), ncrename(1), ncwa(1)

HOMEPAGE

       The NCO homepage at <http://nco.sf.net> contains more information.

                                                                                                      NCFLINT(1)