## NAME

          sample1d - Resampling of 1-D data sets

## SYNOPSIS

          sample1d infile [ -Fl|a|c ] [ -H[nrec] ] [ -Ixinc ] [ -M[flag] ] [
          -Nknotfile ] [ -Sxstart ] [ -Tx-col] [ -bi[s][n] ] [ -bo[s] ]

## 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)
          variable.  Equidistant or arbitrary sampling can be selected.  All
          columns are resampled based on the new sampling interval.  Several
          interpolation 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
               monotonically 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)].

          -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, filter1d