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<!-- Creator     : groff version 1.19.2 -->
<!-- CreationDate: Tue Nov  5 09:45:52 2013 -->
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<title>X2SYS_SOLVE</title>

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<body bgcolor="#ffffff">

<h1 align=center>X2SYS_SOLVE</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="#EXAMPLES">EXAMPLES</a><br>
<a href="#SEE ALSO">SEE ALSO</a><br>

<hr>


<a name="NAME"></a>
<h2>NAME</h2>


<p style="margin-left:11%; margin-top: 1em">x2sys_solve
&minus; Determine systematic corrections from crossovers</p>

<a name="SYNOPSIS"></a>
<h2>SYNOPSIS</h2>


<p style="margin-left:11%; margin-top: 1em"><b>x2sys_solve
&minus;C</b><i>column</i> <b>&minus;T</b><i>TAG</i>
<b>&minus;E</b><i>mode</i> [ <i>COE_list.d</i> ] [
<b>&minus;V</b> ] [ <b>&minus;W</b> ] [ <b>&minus;Z</b> ] [
<b>&minus;bi</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>]]
]</p>

<a name="DESCRIPTION"></a>
<h2>DESCRIPTION</h2>



<p style="margin-left:11%; margin-top: 1em"><b>x2sys_solve</b>
will use the supplied crossover information to solve for
systematic corrections that can then be applied per track to
improve data quality. Several systematic corrections can be
solved for using a least-squares approach. Note: Only one
data column can be processed at the time.</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="3%">



<p style="margin-top: 1em" valign="top"><b>&minus;T</b></p> </td>
<td width="8%"></td>
<td width="78%">


<p style="margin-top: 1em" valign="top">Specify the x2sys
<i>TAG</i> which tracks the attributes of this data
type.</p> </td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">



<p style="margin-top: 1em" valign="top"><b>&minus;C</b></p> </td>
<td width="8%"></td>
<td width="78%">


<p style="margin-top: 1em" valign="top">Specify which data
column you want to process. Needed for proper formatting of
the output correction table and must match the same option
used in <b><A HREF="x2sys_list.html">x2sys_list</A></b> when preparing the input data.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="3%">



<p style="margin-top: 1em" valign="top"><b>&minus;E</b></p> </td>
<td width="8%"></td>
<td width="78%">


<p style="margin-top: 1em" valign="top">The correction type
you wish to model. Choose among the following functions
<i>f</i>(<i>p</i>), where <i>p</i> are the <i>m</i>
parameters per track that we will fit simultaneously using a
least squares approach:</p></td>
</table>

<p style="margin-left:22%;"><b>c</b> will fit
<i>f</i>(<i>p</i>) = <i>a</i> (a constant offset); records
must contain cruise ID1, ID2, COE. <b><br>
d</b> will fit <i>f</i>(<i>p</i>) = <i>a</i> + <i>b</i> *
<i>d</i> (linear drift; <i>d</i> is distance; records must
contain cruise ID1, ID2, d1, d2, COE. <b><br>
g</b> will fit <i>f</i>(<i>p</i>) = <i>a</i> + <i>b</i>
sin(y)^2 (1980-1930 gravity correction); records must
contain cruise ID1, ID2, latitude y, COE. <b><br>
h</b> will fit <i>f</i>(<i>p</i>) = <i>a</i> + <i>b</i>
cos(H) + <i>c</i> cos(2H) + <i>d</i> sin(H) + <i>e</i>
sin(2H) (magnetic heading correction); records must contain
cruise ID1, ID2, heading H, COE. <b><br>
s</b> will fit <i>f</i>(<i>p</i>) = <i>a</i> * z (a unit
scale correction); records must contain cruise ID1, ID2, z1,
z2. <b><br>
t</b> will fit <i>f</i>(<i>p</i>) = <i>a</i> + <i>b</i> *
(<i>t - t0</i>) (linear drift; <i>t0</i> is the start time
of the track); records must contain cruise ID1, ID2, t1-t0,
t2-t0, COE.</p>

<a name="OPTIONS"></a>
<h2>OPTIONS</h2>


<p style="margin-left:11%; margin-top: 1em">No space
between the option flag and the associated arguments.
<i><br>
COE_list.d</i></p>

<p style="margin-left:22%;">Name of file with the required
crossover columns as produced by <b><A HREF="x2sys_list.html">x2sys_list</A></b>. NOTE: If
<b>&minus;bi</b> is used then the first two columns are
expected to hold the integer track IDs; otherwise we expect
those columns to hold the text string names of the two
tracks.</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" valign="top"><b>&minus;V</b></p> </td>
<td width="7%"></td>
<td width="78%">


<p style="margin-top: 1em" valign="top">Selects verbose
mode, which will send progress reports to stderr [Default
runs &quot;silently&quot;].</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">



<p style="margin-top: 1em" valign="top"><b>&minus;W</b></p> </td>
<td width="7%"></td>
<td width="78%">


<p style="margin-top: 1em" valign="top">Means that each
input records has an extra column with the composite weight
for each crossover record. These are used to obtain a
weighted least squares solution [no weights].</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">



<p style="margin-top: 1em" valign="top"><b>&minus;Z</b></p> </td>
<td width="7%"></td>
<td width="78%">


<p style="margin-top: 1em" valign="top">For
<b>&minus;Ed</b> and <b>&minus;Et</b>, determine the
earliest time or shortest distance for each track, then use
these values as the local origin for time duration or
distance calculations. The local origin is then included in
the correction table [Default uses 0].</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="4%">



<p style="margin-top: 1em" valign="top"><b>&minus;bi</b></p> </td>
<td width="7%"></td>
<td width="78%">


<p style="margin-top: 1em" valign="top">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.</p></td>
</table>

<a name="EXAMPLES"></a>
<h2>EXAMPLES</h2>


<p style="margin-left:11%; margin-top: 1em">To fit a simple
bias offset to faa for all tracks under the MGD77 tag,
try</p>


<p style="margin-left:11%; margin-top: 1em"><b><A HREF="x2sys_list.html">x2sys_list</A></b>
COE_data.txt <b>&minus;V &minus;T</b> MGD77 <b>&minus;C</b>
faa <b>&minus;F</b> nc &gt; faa_coe.txt <b><br>
x2sys_solve</b> faa_coe.txt <b>&minus;V &minus;T</b> MGD77
<b>&minus;C</b> faa <b>&minus;E</b> c &gt; coe_table.txt</p>

<p style="margin-left:11%; margin-top: 1em">To fit a faa
linear drift with time instead, try</p>


<p style="margin-left:11%; margin-top: 1em"><b><A HREF="x2sys_list.html">x2sys_list</A></b>
COE_data.txt <b>&minus;V &minus;T</b> MGD77 <b>&minus;C</b>
faa <b>&minus;F</b> nTc &gt; faa_coe.txt <b><br>
x2sys_solve</b> faa_coe.txt <b>&minus;V &minus;T</b> MGD77
<b>&minus;C</b> faa <b>&minus;E</b> t &gt; coe_table.txt</p>

<p style="margin-left:11%; margin-top: 1em">To estimate
heading corrections based on magnetic crossovers associated
with the tag MGD77 from the file COE_data.txt, try</p>


<p style="margin-left:11%; margin-top: 1em"><b><A HREF="x2sys_list.html">x2sys_list</A></b>
COE_data.txt <b>&minus;V &minus;T</b> MGD77 <b>&minus;C</b>
mag <b>&minus;F</b> nhc &gt; mag_coe.txt <b><br>
x2sys_solve</b> mag_coe.txt <b>&minus;V &minus;T</b> MGD77
<b>&minus;C</b> mag <b>&minus;E</b> h &gt; coe_table.txt</p>

<p style="margin-left:11%; margin-top: 1em">To estimate
unit scale corrections based on bathymetry crossovers,
try</p>


<p style="margin-left:11%; margin-top: 1em"><b><A HREF="x2sys_list.html">x2sys_list</A></b>
COE_data.txt <b>&minus;V &minus;T</b> MGD77 <b>&minus;C</b>
depth <b>&minus;F</b> nz &gt; depth_coe.txt <b><br>
x2sys_solve</b> depth_coe.txt <b>&minus;V &minus;T</b> MGD77
<b>&minus;C</b> depth <b>&minus;E</b> s &gt;
coe_table.txt</p>

<a name="SEE ALSO"></a>
<h2>SEE ALSO</h2>



<p style="margin-left:11%; margin-top: 1em"><i><A HREF="x2sys_binlist.html">x2sys_binlist</A></i>(1),
<i><A HREF="x2sys_cross.html">x2sys_cross</A></i>(1), <i><A HREF="x2sys_datalist.html">x2sys_datalist</A></i>(1),
<i><A HREF="x2sys_get.html">x2sys_get</A></i>(1), <i><A HREF="x2sys_init.html">x2sys_init</A></i>(1),
<i><A HREF="x2sys_list.html">x2sys_list</A></i>(1), <i><A HREF="x2sys_put.html">x2sys_put</A></i>(1),
<i><A HREF="x2sys_report.html">x2sys_report</A></i>(1)</p>
<hr>
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