<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <!--Converted with LaTeX2HTML 2002-2-1 (1.71) original version by: Nikos Drakos, CBLU, University of Leeds * revised and updated by: Marcus Hennecke, Ross Moore, Herb Swan * with significant contributions from: Jens Lippmann, Marek Rouchal, Martin Wilck and others --> <HTML> <HEAD> <TITLE>4.4.13 Data gap detection: The -g option</TITLE> <META NAME="description" CONTENT="4.4.13 Data gap detection: The -g option"> <META NAME="keywords" CONTENT="GMT_Docs"> <META NAME="resource-type" CONTENT="document"> <META NAME="distribution" CONTENT="global"> <META NAME="Generator" CONTENT="LaTeX2HTML v2002-2-1"> <META HTTP-EQUIV="Content-Style-Type" CONTENT="text/css"> <LINK REL="STYLESHEET" HREF="GMT_Docs.css"> <LINK REL="next" HREF="node55.html"> <LINK REL="previous" HREF="node53.html"> <LINK REL="up" HREF="node36.html"> <LINK REL="next" HREF="node55.html"> </HEAD> <BODY bgcolor="#ffffff"> <!--Navigation Panel--> <A NAME="tex2html3284" HREF="node55.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> <A NAME="tex2html3278" HREF="node36.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> <A NAME="tex2html3272" HREF="node53.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> <A NAME="tex2html3280" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> <A NAME="tex2html3282" HREF="node255.html"> <IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="index.png"></A> <BR> <B> Next:</B> <A NAME="tex2html3285" HREF="node55.html">4.4.14 Multiple segment data:</A> <B> Up:</B> <A NAME="tex2html3279" HREF="node36.html">4.4 Standardized command line</A> <B> Previous:</B> <A NAME="tex2html3273" HREF="node53.html">4.4.12 Data type selection:</A> <B> <A NAME="tex2html3281" HREF="node1.html">Contents</A></B> <B> <A NAME="tex2html3283" HREF="node255.html">Index</A></B> <BR> <BR> <!--End of Navigation Panel--> <H2><A NAME="SECTION0012413000000000000000"> 4.4.13 Data gap detection: The <B>-g</B> option</A> </H2> <A NAME="18113"></A> <P> <A NAME="tex2html1114" HREF="http://gmt.soest.hawaii.edu"><B>GMT</B></A> has several mechanisms that can determine line segmentation. Typically, data segments are separated by multiple segment header records (see section <A HREF="node55.html#sec:multsegments">4.4.14</A> on <B>-m</B> below). However, if key data columns contain a NaN we may also use that information to break lines into multiple segments. This behavior is modified by the parameter <B>NAN_RECORDS</B> which by default is set to <I>skip</I>, meaning such records are considered bad and simply skipped. If you wish such records to indicate a segment boundary then set this parameter to <I>pass</I>. Finally, you may wish to indicate gaps based on the data values themselves. The <B>-g</B> option is used to detect gaps based on one or more criteria (use <B>-g+</B> if <I>all</I> the criteria must be met; otherwise only one of the specified criteria needs to be met to signify a data gap). Gaps can be based on excessive jumps in the <I>x</I>- or <I>y</I>-coordinates (<B>-gx</B> or <B>-gy</B>), or on the distance between points (<B>-gd</B>). Append the <I>gap</I> distance and optionally a unit for actual distances. For geographic data the optional unit may be m<B>e</B>ter [Default], <B>k</B>ilometer, <B>m</B>iles, or <B>n</B>autical miles. For programs that maps data to map coordinates you can optionally specify these criteria to apply to the projected coordinates (by using upper-case <B>-gX</B>, <B>-gY</B> or<B>-gD</B>). In that case, choose from <B>i</B>nch, <B>c</B>entimeter, <B>m</B>eter, or <B>p</B>oints. [Default unit is controlled by <B>MEASURE_UNIT</B>]. Note: For <B>-gx</B> or <B>-gy</B> with time data the unit is instead controlled by <B>TIME_UNIT</B>. <P> <HR> <!--Navigation Panel--> <A NAME="tex2html3284" HREF="node55.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> <A NAME="tex2html3278" HREF="node36.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> <A NAME="tex2html3272" HREF="node53.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> <A NAME="tex2html3280" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> <A NAME="tex2html3282" HREF="node255.html"> <IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="index.png"></A> <BR> <B> Next:</B> <A NAME="tex2html3285" HREF="node55.html">4.4.14 Multiple segment data:</A> <B> Up:</B> <A NAME="tex2html3279" HREF="node36.html">4.4 Standardized command line</A> <B> Previous:</B> <A NAME="tex2html3273" HREF="node53.html">4.4.12 Data type selection:</A> <B> <A NAME="tex2html3281" HREF="node1.html">Contents</A></B> <B> <A NAME="tex2html3283" HREF="node255.html">Index</A></B> <!--End of Navigation Panel--> <ADDRESS> Paul Wessel 2010-01-14 </ADDRESS> </BODY> </HTML>
