NAME

       ncflint - netCDF File Interpolator

SYNTAX

       ncflint   [-3]   [-4]   [-5]   [-6]   [-7]   [-A]   [--bfr   sz_byt][-C][-c][--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]  [--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] [--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 © 1995-2018 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.

       ncap(1),  ncap2(1),  ncatted(1),  ncbo(1),  ncclimo(1),  nces(1), ncecat(1), ncflint(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)