Provided by: nco_4.7.9-1_amd64

**NAME**

ncflint - netCDF File Interpolator

**SYNTAX**

ncflint [-3] [-4] [-5] [-6] [-7] [-A] [--bfrsz_byt][-C][-c][--cnk_bytsz_byt][--cnk_cshsz_byt][--cnk_dmnnm,sz_lmn] [--cnk_mapmap] [--cnk_minsz_byt] [--cnk_plcplc] [--cnk_sclsz_lmn][-Ddbg_lvl] [-ddim,[min][,[max]]] [-F] [--fl_fmt=fmt] [--fix_rec_crd] [-Ggpe_dsc] [-ggrp[,...]] [--glbatt_name=att_val]] [-h] [--hdf] [--hdr_padsz_byt][--hpss_try][-ivar,val3][-Ldfl_lvl][-lpath] [--msa] [-N] [--no_cll_msr] [--no_frm_trm] [--no_tmp_fl] [-O] [-ppath] [--ppcvar1[,var2[,...]]=prc]] [-R] [-r] [--ram_all] [-tthr_nbr] [--unn] [-vvar[,...]] [-wwgt[,wgt2]] [-Xbox] [-x]file1file2file3

**DESCRIPTION**

ncflintcreates 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 fromfile_1.There are two conceptually distinct methods of usingncflint.The first method is to specify the weight each input file is to have in the output file. In this method, the valueval3of a variable in the output filefile_3is determined from its valuesval1andval2in the two input files according towgt1*val1+wgt2*val2Here at leastwgt1,and, optionally,wgt2,are specified on the command line with the-w(or--weightor--wgt_var) switch. If onlywgt1is specified thenwgt2is automatically computed aswgt2=1-wgt1.Note that weights larger than 1 are allowed. Thus it is possible to specifywgt1=2andwgt2=-3.One can use this functionality to multiply all the values in a given file by a constant. The second method of usingncflintis to specify the interpolation option with-i(or with the--ntpor--interpolatelong options). This is really the inverse of the first method in the following sense. When the user specifies the weights directly,ncflinthas 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 variablevarthat is known a priori. In this case, the implied weights can always be inferred by examining the values ofvarin the input files. This results in one equation in two unknowns,wgt1andwgt2: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 specifiesvarandval3with the-ioption.ncflintwill computewgt1andwgt2,and use these weights on all variables to generate the output file. Althoughvarmay have any number of dimensions in the input files, it must represent a single, scalar value. Thus any dimensions associated withvarmust be "degenerate", i.e., of size one. If neither-inor-wis specified on the command line,ncflintdefaults to weighting each input file equally in the output file. This is equivalent to specifying-w0.5 or-w0.5,0.5. Attempting to specify both-iand-wmethods in the same command is an error.ncflintis programmed not to interpolate variables of typeNC_CHARandNC_BYTE.This behavior is hardcoded.

**AUTHOR**

NCOmanual 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 forNCOis maintained as a Texinfo manual called theNCOUsersGuide.BecauseNCOis mathematical in nature, the documentation includes TeX-intensive portions not viewable on character-based displays. Hence the only complete and authoritative versions of theNCOUsersGuideare 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 theinfoandNCOprograms are properly installed at your site, the commandinfoncoshould 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**

TheNCOhomepage at <http://nco.sf.net> contains more information. NCFLINT(1)