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<h1 align="center">SAMPLE1D</h1>
<a href="#NAME">NAME</a><br>
<a href="#SYNOPSIS">SYNOPSIS</a><br>
<a href="#DESCRIPTION">DESCRIPTION</a><br>
<a href="#OPTIONS">OPTIONS</a><br>
<a href="#ASCII FORMAT PRECISION">ASCII FORMAT PRECISION</a><br>
<a href="#CALENDAR TIME SAMPLING">CALENDAR TIME SAMPLING</a><br>
<a href="#EXAMPLES">EXAMPLES</a><br>
<a href="#SEE ALSO">SEE ALSO</a><br>
<hr>
<h2>NAME
<a name="NAME"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">sample1d
− Resampling of 1-D data sets</p>
<h2>SYNOPSIS
<a name="SYNOPSIS"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>sample1d</b>
<i>infile</i> [ <b>−Fl</b>|<b>a</b>|<b>c</b>|<b>n</b>
] [ <b>−H</b>[<b>i</b>][<i>nrec</i>] ] [
<b>−I</b><i>xinc</i> ] [
<b>−N</b><i>knotfile</i> ] [
<b>−S</b><i>xstart</i> ] [ <b>−T</b><i>x_col</i>
] [ <b>−V</b> ] [
<b>−b</b>[<b>i</b>|<b>o</b>][<b>s</b>|<b>S</b>|<b>d</b>|<b>D</b>[<i>ncol</i>]|<b>c</b>[<i>var1</i><b>/</b><i>...</i>]]
] [ <b>−f</b>[<b>i</b>|<b>o</b>]<i>colinfo</i> ] [
<b>−m</b>[<b>i</b>|<b>o</b>][<i>flag</i>] ]</p>
<h2>DESCRIPTION
<a name="DESCRIPTION"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><b>sample1d</b>
reads a multi-column ASCII [or binary] data set from file
[or standard input] and interpolates the timeseries/profile
at locations where the user needs the values. The user must
provide the column number of the independent (monotonically
increasing <b>or</b> decreasing) variable. Equidistant or
arbitrary sampling can be selected. All columns are
resampled based on the new sampling interval. Several
interpolation schemes are available. Extrapolation outside
the range of the input data is not supported.</p>
<table width="100%" border="0" rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="9%">
<p><i>infile</i></p></td>
<td width="2%"></td>
<td width="78%">
<p>This is a multi-column ASCII [of binary, see
<b>−b</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, <b>sample1d</b> reads from
standard input.</p></td></tr>
</table>
<h2>OPTIONS
<a name="OPTIONS"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">No space
between the option flag and the associated arguments.</p>
<table width="100%" border="0" rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">
<p style="margin-top: 1em"><b>−F</b></p></td>
<td width="7%"></td>
<td width="78%">
<p style="margin-top: 1em">Choose from <b>l</b> (Linear),
<b>a</b> (Akima spline), <b>c</b> (natural cubic spline),
and <b>n</b> (no interpolation: nearest point) [Default is
<b>−Fa</b>]. You may change the default interpolant;
see <b><A HREF="gmtdefaults.html#INTERPOLANT">INTERPOLANT</A></b> in your .gmtdefaults4 file.</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">
<p><b>−H</b></p></td>
<td width="7%"></td>
<td width="78%">
<p>Input file(s) has header record(s). If used, the default
number of header records is <b><A HREF="gmtdefaults.html#N_HEADER_RECS">N_HEADER_RECS</A></b>. Use
<b>−Hi</b> if only input data should have header
records [Default will write out header records if the input
data have them]. Blank lines and lines starting with # are
always skipped.</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">
<p><b>−I</b></p></td>
<td width="7%"></td>
<td width="78%">
<p><i>xinc</i> defines the sampling interval. [Default is
the separation between the first and second abscissa point
in the <i>infile</i>]</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">
<p><b>−N</b></p></td>
<td width="7%"></td>
<td width="78%">
<p><i>knotfile</i> is an optional ASCII file with the x
locations where the data set will be resampled in the first
column. Note: if <b>−H</b> is selected it applies to
both <i>infile</i> and <i>knotfile</i>.</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">
<p><b>−S</b></p></td>
<td width="7%"></td>
<td width="78%">
<p>For equidistant sampling, <i>xstart</i> indicates the
location of the first output value. [Default is the smallest
even multiple of <i>xinc</i> inside the range of
<i>infile</i>]</p> </td></tr>
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<td width="11%"></td>
<td width="4%">
<p><b>−T</b></p></td>
<td width="7%"></td>
<td width="78%">
<p>Sets the column number of the independent variable
[Default is 0 (first)].</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">
<p><b>−V</b></p></td>
<td width="7%"></td>
<td width="78%">
<p>Selects verbose mode, which will send progress reports
to stderr [Default runs "silently"].</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">
<p><b>−bi</b></p></td>
<td width="7%"></td>
<td width="78%">
<p>Selects binary input. Append <b>s</b> for single
precision [Default is <b>d</b> (double)]. Uppercase <b>S</b>
or <b>D</b> will force byte-swapping. Optionally, append
<i>ncol</i>, the number of columns in your binary input file
if it exceeds the columns needed by the program. Or append
<b>c</b> if the input file is netCDF. Optionally, append
<i>var1</i><b>/</b><i>var2</i><b>/</b><i>...</i> to specify
the variables to be read. [Default is 2 (or at least the
number of columns implied by <b>−T</b>)].</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">
<p><b>−bo</b></p></td>
<td width="7%"></td>
<td width="78%">
<p>Selects binary output. Append <b>s</b> for single
precision [Default is <b>d</b> (double)]. Uppercase <b>S</b>
or <b>D</b> will force byte-swapping. Optionally, append
<i>ncol</i>, the number of desired columns in your binary
output file. [Default is same as input].</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">
<p><b>−f</b></p></td>
<td width="7%"></td>
<td width="78%">
<p>Special formatting of input and/or output columns (time
or geographical data). Specify <b>i</b> or <b>o</b> to make
this apply only to input or output [Default applies to
both]. Give one or more columns (or column ranges) separated
by commas. Append <b>T</b> (absolute calendar time),
<b>t</b> (relative time in chosen <b><A HREF="gmtdefaults.html#TIME_UNIT">TIME_UNIT</A></b> since
<b><A HREF="gmtdefaults.html#TIME_EPOCH">TIME_EPOCH</A></b>), <b>x</b> (longitude), <b>y</b>
(latitude), or <b>f</b> (floating point) to each column or
column range item. Shorthand
<b>−f</b>[<b>i</b>|<b>o</b>]<b>g</b> means
<b>−f</b>[<b>i</b>|<b>o</b>]0<b>x</b>,1<b>y</b>
(geographic coordinates).</p></td></tr>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">
<p><b>−m</b></p></td>
<td width="7%"></td>
<td width="78%">
<p>Multiple segment file(s). Segments are separated by a
special record. For ASCII files the first character must be
<i>flag</i> [Default is ’>’]. For binary
files all fields must be NaN and <b>−b</b> must set
the number of output columns explicitly. By default the
<b>−m</b> setting applies to both input and output.
Use <b>−mi</b> and <b>−mo</b> to give separate
settings to input and output.</p></td></tr>
</table>
<h2>ASCII FORMAT PRECISION
<a name="ASCII FORMAT PRECISION"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">The ASCII
output formats of numerical data are controlled by
parameters in your .gmtdefaults4 file. Longitude and
latitude are formatted according to
<b><A HREF="gmtdefaults.html#OUTPUT_DEGREE_FORMAT">OUTPUT_DEGREE_FORMAT</A></b>, whereas other values are
formatted according to <b><A HREF="gmtdefaults.html#D_FORMAT">D_FORMAT</A></b>. Be aware that the
format in effect can lead to loss of precision in the
output, which can lead to various problems downstream. If
you find the output is not written with enough precision,
consider switching to binary output (<b>−bo</b> if
available) or specify more decimals using the
<b><A HREF="gmtdefaults.html#D_FORMAT">D_FORMAT</A></b> setting.</p>
<h2>CALENDAR TIME SAMPLING
<a name="CALENDAR TIME SAMPLING"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">If the abscissa
are calendar times then you must use the <b>−f</b>
option to indicate this. Furthermore, <b>−I</b> then
expects an increment in the current <b><A HREF="gmtdefaults.html#TIME_UNIT">TIME_UNIT</A></b> units.
There is not yet support for variable intervals such as
months.</p>
<h2>EXAMPLES
<a name="EXAMPLES"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em">To resample the
file profiles.tdgmb, which contains
(time,distance,gravity,magnetics,bathymetry) records, at 1km
equidistant intervals using Akima’s spline, use</p>
<p style="margin-left:11%; margin-top: 1em"><b>sample1d</b>
profiles.tdgmb <b>−I</b> 1 <b>−Fa −T</b> 1
> profiles_equi_d.tdgmb</p>
<p style="margin-left:11%; margin-top: 1em">To resample the
file depths.dt at positions listed in the file grav_pos.dg,
using a cubic spline for the interpolation, use</p>
<p style="margin-left:11%; margin-top: 1em"><b>sample1d</b>
depths.dt <b>−N</b> grav_pos.dg <b>−Fc</b> >
new_depths.dt</p>
<h2>SEE ALSO
<a name="SEE ALSO"></a>
</h2>
<p style="margin-left:11%; margin-top: 1em"><i><A HREF="GMT.html">GMT</A></i>(1),
<i><A HREF="filter1d.html">filter1d</A></i>(1)</p>
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