1NCFLINT(1) General Commands Manual NCFLINT(1)
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6 ncflint - netCDF File Interpolator
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9 ncflint [-3] [-4] [-5] [-6] [-7] [-A] [--bfr sz_byt][-C][-c][--cnk_byt
10 sz_byt][--cnk_csh sz_byt][--cnk_dmn nm,sz_lmn] [--cnk_map map]
11 [--cnk_min sz_byt] [--cnk_plc plc] [--cnk_scl sz_lmn][-D dbg_lvl] [-d
12 dim,[ min][,[ max]]] [-F] [--fl_fmt=fmt] [--fix_rec_crd] [-G gpe_dsc]
13 [-g grp[,...]] [--glb att_name= att_val]] [-h] [--hdf] [--hdr_pad
14 sz_byt][--hpss_try] [-i var,val3][-L dfl_lvl][-l path] [--msa] [-N]
15 [--no_cll_msr] [--no_frm_trm] [--no_tmp_fl] [-O] [-p path] [--ppc
16 var1[, var2[,...]]= prc]] [-R] [-r] [--ram_all] [-t thr_nbr] [--unn]
17 [-v var[,...]] [-w wgt[, wgt2]] [-X box] [-x] file1 file2 file3
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20 ncflint creates an output file that is a linear combination of the
21 input files. This linear combination can be a weighted average, a nor‐
22 malized weighted average, or an interpolation of the input files.
23 Coordinate variables are not acted upon in any case, they are simply
24 copied from file_1.
25 There are two conceptually distinct methods of using ncflint. The
26 first method is to specify the weight each input file is to have in the
27 output file. In this method, the value val3 of a variable in the out‐
28 put file file_3 is determined from its values val1 and val2 in the two
29 input files according to wgt1*val1+wgt2*val2
30 Here at least wgt1, and, optionally, wgt2, are specified on the command
32 line with the -w (or --weight or --wgt_var ) switch. If only wgt1 is
33 specified then wgt2 is automatically computed as wgt2=1-wgt1. Note
34 that weights larger than 1 are allowed. Thus it is possible to specify
35 wgt1=2 and wgt2=-3. One can use this functionality to multiply all the
36 values in a given file by a constant.
37 The second method of using ncflint is to specify the interpolation
39 option with -i (or with the --ntp or --interpolate long options). This
40 is really the inverse of the first method in the following sense. When
41 the user specifies the weights directly, ncflint has no work to do
42 besides multiplying the input values by their respective weights and
43 adding the results together to produce the output values. This assumes
44 it is the weights that are known a priori. In another class of cases
45 it is the "arrival value" (i.e., val3 ) of a particular variable var
46 that is known a priori. In this case, the implied weights can always
47 be inferred by examining the values of var in the input files. This
48 results in one equation in two unknowns, wgt1 and wgt2:
49 val3=wgt1*val1+wgt2*val2.
50 Unique determination of the weights requires imposing the additional
52 constraint of normalization on the weights: wgt1+wgt2=1. Thus, to use
53 the interpolation option, the user specifies var and val3 with the -i
54 option. ncflint will compute wgt1 and wgt2, and use these weights on
55 all variables to generate the output file. Although var may have any
56 number of dimensions in the input files, it must represent a single,
57 scalar value. Thus any dimensions associated with var must be "degen‐
58 erate", i.e., of size one.
59 If neither -i nor -w is specified on the command line, ncflint
61 defaults to weighting each input file equally in the output file. This
62 is equivalent to specifying -w 0.5 or -w 0.5,0.5. Attempting to spec‐
63 ify both -i and -w methods in the same command is an error.
64 ncflint is programmed not to interpolate variables of type NC_CHAR and
66 NC_BYTE. This behavior is hardcoded.
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70 NCO manual pages written by Charlie Zender and originally formatted by
71 Brian Mays.
72
75 Report bugs to <http://sf.net/bugs/?group_id=3331>.
76
79 Copyright © 1995-2018 Charlie Zender
80 This is free software; see the source for copying conditions. There is
81 NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
82 PURPOSE.
83
86 The full documentation for NCO is maintained as a Texinfo manual called
87 the NCO Users Guide. Because NCO is mathematical in nature, the docu‐
88 mentation includes TeX-intensive portions not viewable on character-
89 based displays. Hence the only complete and authoritative versions of
90 the NCO Users Guide are the PDF (recommended), DVI, and Postscript ver‐
91 sions at <http://nco.sf.net/nco.pdf>, <http://nco.sf.net/nco.dvi>, and
92 <http://nco.sf.net/nco.ps>, respectively. HTML and XML versions are
93 available at <http://nco.sf.net/nco.html> and
94 <http://nco.sf.net/nco.xml>, respectively.
95 If the info and NCO programs are properly installed at your site, the
97 command
98 info nco
100 should give you access to the complete manual, except for the TeX-
102 intensive portions.
103 ncap(1), ncap2(1), ncatted(1), ncbo(1), ncclimo(1), nces(1), ncecat(1),
105 ncflint(1), ncks(1), nco(1), ncpdq(1), ncra(1), ncrcat(1), ncremap(1),
106 ncrename(1), ncwa(1)
107
110 The NCO homepage at <http://nco.sf.net> contains more information.
111 NCFLINT(1)