<!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>O.3.4 Label placement at simple line intersections</TITLE> <META NAME="description" CONTENT="O.3.4 Label placement at simple line intersections"> <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="node247.html"> <LINK REL="previous" HREF="node245.html"> <LINK REL="up" HREF="node242.html"> <LINK REL="next" HREF="node247.html"> </HEAD> <BODY bgcolor="#ffffff"> <!--Navigation Panel--> <A NAME="tex2html6177" HREF="node247.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> <A NAME="tex2html6171" HREF="node242.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> <A NAME="tex2html6165" HREF="node245.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> <A NAME="tex2html6173" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> <A NAME="tex2html6175" HREF="node256.html"> <IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="index.png"></A> <BR> <B> Next:</B> <A NAME="tex2html6178" HREF="node247.html">O.3.5 Label placement at</A> <B> Up:</B> <A NAME="tex2html6172" HREF="node242.html">O.3 Examples of Contour</A> <B> Previous:</B> <A NAME="tex2html6166" HREF="node245.html">O.3.3 Prescribed label placements</A> <B> <A NAME="tex2html6174" HREF="node1.html">Contents</A></B> <B> <A NAME="tex2html6176" HREF="node256.html">Index</A></B> <BR> <BR> <!--End of Navigation Panel--> <H2><A NAME="SECTION003234000000000000000"> O.3.4 Label placement at simple line intersections</A> </H2> <P> Often, it will suffice to place contours at the imaginary intersections between the contour lines and a well-placed straight line segment. The <B>-Gl</B> or <B>-GL</B> algorithms work well in those cases: <P> <BR CLEAR="ALL"> <HR> <BR> <PRE>pscoast -R50/160/-15/15 -JM5.3i -Glightgray -A500 -K -P > GMT_App_O_4.ps grdcontour geoid.nc -J -O -B20f10WSne -C10 -A20+d+s8 -GLZ-/Z+ -S10 -T:LH >> GMT_App_O_4.ps </PRE> <BR CLEAR="ALL"> <HR> <P> The obvious choice in this example is to specify a great circle between the high and the low, thus placing all labels between these extrema. <P> <DIV ALIGN="CENTER"><A NAME="fig:GMT_App_O_4"></A><A NAME="33531"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure O.4:</STRONG> Labels are placed at the intersections between contours and the great circle specified in the <B>-GL</B> option.</CAPTION> <TR><TD> <DIV ALIGN="CENTER"><IMG WIDTH="653" HEIGHT="195" ALIGN="BOTTOM" BORDER="0" SRC="img300.png" ALT="\includegraphics{scripts/GMT_App_O_4}"></DIV></TD></TR> </TABLE> </DIV> The thin debug line in Figure <A HREF="#fig:GMT_App_O_4">O.4</A> shows the great circle and the intersections where labels are plotted. Note that any number of such lines could be specified; here we are content with just one. <P> <HR> <!--Navigation Panel--> <A NAME="tex2html6177" HREF="node247.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> <A NAME="tex2html6171" HREF="node242.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> <A NAME="tex2html6165" HREF="node245.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> <A NAME="tex2html6173" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> <A NAME="tex2html6175" HREF="node256.html"> <IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="index.png"></A> <BR> <B> Next:</B> <A NAME="tex2html6178" HREF="node247.html">O.3.5 Label placement at</A> <B> Up:</B> <A NAME="tex2html6172" HREF="node242.html">O.3 Examples of Contour</A> <B> Previous:</B> <A NAME="tex2html6166" HREF="node245.html">O.3.3 Prescribed label placements</A> <B> <A NAME="tex2html6174" HREF="node1.html">Contents</A></B> <B> <A NAME="tex2html6176" HREF="node256.html">Index</A></B> <!--End of Navigation Panel--> <ADDRESS> Paul Wessel 2010-07-14 </ADDRESS> </BODY> </HTML>