<!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>5.1.3 Cartesian power projection</TITLE> <META NAME="description" CONTENT="5.1.3 Cartesian power projection"> <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="previous" HREF="node82.html"> <LINK REL="up" HREF="node77.html"> <LINK REL="next" HREF="node84.html"> </HEAD> <BODY bgcolor="#ffffff"> <!--Navigation Panel--> <A NAME="tex2html3733" HREF="node84.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> <A NAME="tex2html3727" HREF="node77.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> <A NAME="tex2html3723" HREF="node82.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> <A NAME="tex2html3729" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> <A NAME="tex2html3731" HREF="node256.html"> <IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="index.png"></A> <BR> <B> Next:</B> <A NAME="tex2html3734" HREF="node84.html">5.2 Linear projection with</A> <B> Up:</B> <A NAME="tex2html3728" HREF="node77.html">5.1 Cartesian transformations</A> <B> Previous:</B> <A NAME="tex2html3724" HREF="node82.html">5.1.2 Cartesian logarithmic projection</A> <B> <A NAME="tex2html3730" HREF="node1.html">Contents</A></B> <B> <A NAME="tex2html3732" HREF="node256.html">Index</A></B> <BR> <BR> <!--End of Navigation Panel--> <H2><A NAME="SECTION001313000000000000000"></A> <A NAME="21055"></A> <A NAME="21056"></A> <A NAME="21057"></A> <BR> 5.1.3 Cartesian power projection </H2> <P> <DIV ALIGN="CENTER"><A NAME="fig:GMT_pow"></A><A NAME="21201"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 5.5:</STRONG> Exponential or power transformation of <IMG WIDTH="11" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" SRC="img4.png" ALT="$x$">-coordinates.</CAPTION> <TR><TD> <DIV ALIGN="CENTER"><IMG WIDTH="391" HEIGHT="209" ALIGN="BOTTOM" BORDER="0" SRC="img100.png" ALT="\includegraphics{scripts/GMT_pow}"></DIV></TD></TR> </TABLE> </DIV> <P> This projection uses <!-- MATH $u' = a u^b + c$ --> <IMG WIDTH="82" HEIGHT="35" ALIGN="MIDDLE" BORDER="0" SRC="img101.png" ALT="$u' = a u^b + c$"> and allows us to explore exponential relationships like <I>x<IMG WIDTH="12" HEIGHT="15" ALIGN="BOTTOM" BORDER="0" SRC="img102.png" ALT="$^p$"></I> versus <I>y<IMG WIDTH="11" HEIGHT="15" ALIGN="BOTTOM" BORDER="0" SRC="img103.png" ALT="$^q$"></I>. While <IMG WIDTH="13" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" SRC="img104.png" ALT="$p$"> and <IMG WIDTH="12" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" SRC="img105.png" ALT="$q$"> can be any values, we will select <IMG WIDTH="53" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" SRC="img106.png" ALT="$p = 0.5$"> and <IMG WIDTH="39" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" SRC="img107.png" ALT="$q = 1$"> which means we will plot <IMG WIDTH="11" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" SRC="img4.png" ALT="$x$"> versus <IMG WIDTH="25" HEIGHT="33" ALIGN="MIDDLE" BORDER="0" SRC="img3.png" ALT="$\sqrt {x}$">. We indicate this scaling by appending a <B>p</B> (lower case P) followed by the desired exponent, in our case 0.5. Since <IMG WIDTH="39" HEIGHT="29" ALIGN="MIDDLE" BORDER="0" SRC="img107.png" ALT="$q = 1$"> we do not need to specify <B>p</B>1 since it is identical to the linear transformation. Thus our command becomes <P> <BR CLEAR="ALL"> <HR> <BR> <PRE>psxy -R0/100/0/10 -Jx0.3ip0.5/0.15i -Ba1p/a2f1WSne -Wthick -P -K sqrt.d > GMT_pow.ps psxy -R -J -Sc0.075i -Gwhite -W -O sqrt.d10 >> GMT_pow.ps </PRE> <BR CLEAR="ALL"> <HR><A NAME="21066"></A> <A NAME="21067"></A> <A NAME="21068"></A> <A NAME="21107"></A> <P> <HR> <!--Navigation Panel--> <A NAME="tex2html3733" HREF="node84.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> <A NAME="tex2html3727" HREF="node77.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> <A NAME="tex2html3723" HREF="node82.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> <A NAME="tex2html3729" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> <A NAME="tex2html3731" HREF="node256.html"> <IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="index.png"></A> <BR> <B> Next:</B> <A NAME="tex2html3734" HREF="node84.html">5.2 Linear projection with</A> <B> Up:</B> <A NAME="tex2html3728" HREF="node77.html">5.1 Cartesian transformations</A> <B> Previous:</B> <A NAME="tex2html3724" HREF="node82.html">5.1.2 Cartesian logarithmic projection</A> <B> <A NAME="tex2html3730" HREF="node1.html">Contents</A></B> <B> <A NAME="tex2html3732" HREF="node256.html">Index</A></B> <!--End of Navigation Panel--> <ADDRESS> Paul Wessel 2010-07-14 </ADDRESS> </BODY> </HTML>