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]  [-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)