ncflint (1) - Linux Manuals
ncflint: netCDF File Interpolator
NAME
ncflint - netCDF File InterpolatorSYNTAX
ncflint [-3] [-4] [-6] [-7] [-A] [--bfr sz][-C][-c][-D dbg_lvl] [-d dim,[ min][,[ max]]] [-F] [--fix_rec_crd] [-G gpe_dsc] [-g grp[,...]] [-h] [--hdf] [--hdr_pad sz] [-i var,val3][-L dfl_lvl][-l path] [--msa] [--no_tmp_fl] [-O] [-p path] [-R] [-r] [--ram_all] [-t thr_nbr] [--unn] [-v var[,...]] [-w wgt[, wgt2]] [-X box] [-x] file1 file2 file3DESCRIPTION
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.
Here at least
wgt1,
and, optionally,
wgt2,
are specified on the command line with the
-w
(or
--weight
or
--wgt_var
) switch. If only
IR 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.
ncflint
is programmed not to interpolate variables of type
NC_CHAR
and
NC_BYTE.
This behavior is hardcoded.
If the
info
and
NCO
programs are properly installed at your site, the command
should give you access to the complete manual, except for the
TeX-intensive portions.
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 © 1995-2014 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.
HOMEPAGE
The
NCO
homepage at <http://nco.sf.net> contains more information.
SEE ALSO
The full documentation for
NCO
is maintained as a Texinfo manual called the
NCO User's 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 User's 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.