SAMPLE1D(l) SAMPLE1D(l)
NAME
sample1d - Resampling of 1-D data sets
SYNOPSIS
sample1d infile [ -Fl|a|c ] [ -H[nrec] ] [ -Ixinc ] [ -M[flag] ] [ -Nknotfile ] [ -Sxstart ] [ -Tx-col] [ -V ] [ -bi[s][n] ] [ -bo[s][n] ]
DESCRIPTION
sample1d reads a multi-column ASCII [or binary] data set from file [or standard input] and resamples the timeseries/profile at locations
where the user needs the values. The user must provide the column number of the independent (monotonically increasing or decreasing) vari-
able. Equidistant or arbitrary sampling can be selected. All columns are resampled based on the new sampling interval. Several interpola-
tion schemes are available.
infile This is a multi-column ASCII [of binary, see -b] file with one column containing the independent variable (which must be monotoni-
cally in/de-creasing) and the remaining columns holding misc. data values. If no file is provided, sample1d reads from standard
input.
OPTIONS
No space between the option flag and the associated arguments.
-F Choose from l (Linear), a (Akima spline), and c (natural cubic spline) [Default is -Fa]. You may change the default interpolant;
see INTERPOLANT in your .gmtdefaults file.
-H Input file(s) has Header record(s). Number of header records can be changed by editing your .gmtdefaults file. If used, GMT default
is 1 header record.
-I xinc defines the sampling interval. [Default is the separation between the first and second abcissa point in the infile]
-M Multiple segment file. Segments are separated by a record whose first character is flag. [Default is '>'].
-N knotfile is an optional ASCII file with the x locations where the data set will be resampled in the first column
-S For equidistant sampling, xstart indicates the location of the first output value. [Default is the smallest even multiple of xinc
inside the range of infile]
-T Sets the column number of the independent variable [Default is 0 (first)].
-V Selects verbose mode, which will send progress reports to stderr [Default runs "silently"].
-bi Selects binary input. Append s for single precision [Default is double]. Append n for the number of columns in the binary file(s).
[Default is 2 (or at least the number of columns implied by -T].
-bo Selects binary output. Append s for single precision [Default is double].
EXAMPLES
To resample the file profiles.tdgmb, which contains (time,distance,gravity,magnetics,bathymetry) records, at 1km equidistant intervals
using Akima's spline, try'
sample1d profiles.tdgmb -I1 -Fa -T1 > profiles_equi_d.tdgmb
To resample the file depths.dt at positions listed in the file grav_pos.dg, using a cubic spline for the interpolation, try
sample1d depths.dt -Ngrav_pos.dg -Fc > new_depths.dt
SEE ALSO
gmt(1gmt), filter1d(1gmt)
1 Jan 2004 SAMPLE1D(l)
