<!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>4.15 Color palette tables</TITLE> <META NAME="description" CONTENT="4.15 Color palette tables"> <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="node70.html"> <LINK REL="previous" HREF="node66.html"> <LINK REL="up" HREF="node30.html"> <LINK REL="next" HREF="node68.html"> </HEAD> <BODY bgcolor="#ffffff"> <!--Navigation Panel--> <A NAME="tex2html3464" HREF="node68.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> <A NAME="tex2html3458" HREF="node30.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> <A NAME="tex2html3452" HREF="node66.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> <A NAME="tex2html3460" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> <A NAME="tex2html3462" HREF="node255.html"> <IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="index.png"></A> <BR> <B> Next:</B> <A NAME="tex2html3465" HREF="node68.html">4.15.1 Categorical CPT files</A> <B> Up:</B> <A NAME="tex2html3459" HREF="node30.html">4. General features</A> <B> Previous:</B> <A NAME="tex2html3453" HREF="node66.html">4.14 Specifying area fill</A> <B> <A NAME="tex2html3461" HREF="node1.html">Contents</A></B> <B> <A NAME="tex2html3463" HREF="node255.html">Index</A></B> <BR> <BR> <!--End of Navigation Panel--> <H1><A NAME="SECTION0012150000000000000000"> 4.15 Color palette tables</A> </H1> <P> <A NAME="17681"></A> <A NAME="17682"></A> <P> Several programs, such as those which read 2-D gridded data sets and create colored images or shaded reliefs, need to be told what colors to use and over what <I>z</I>-range each color applies. This is the purpose of the color palette table (cpt-file). These files may also be used by <A NAME="tex2html1147" HREF="../man/psxy.html"><I><B>psxy</B></I></A><A NAME="18836"></A> and <A NAME="tex2html1148" HREF="../man/psxyz.html"><I><B>psxyz</B></I></A><A NAME="18841"></A> to plot color-filled symbols. For most applications, you will simply create a cpt-file using the tool <A NAME="tex2html1149" HREF="../man/makecpt.html"><I><B>makecpt</B></I></A><A NAME="18846"></A> which will take an existing color table and resample it to fit your chosen data range, or use <A NAME="tex2html1150" HREF="../man/grd2cpt.html"><I><B>grd2cpt</B></I></A><A NAME="18851"></A> to build a cpt-file based on the data distribution in one or more given grid files. However, in some situations you will need to make a cpt-file by hand or using text tools like <I>awk</I><A NAME="18855"></A> or <I>perl</I><A NAME="18858"></A>. <P> Color palette tables (CPT) comes in two flavors: (1) Those designed to work with categorical data (e.g., data where interpolation of values is undefined) and (2) those designed for regular, continuously-varying data. <P> <BR><HR> <!--Table of Child-Links--> <A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></A> <UL> <LI><A NAME="tex2html3466" HREF="node68.html">4.15.1 Categorical CPT files</A> <LI><A NAME="tex2html3467" HREF="node69.html">4.15.2 Regular CPT files</A> </UL> <!--End of Table of Child-Links--> <HR> <!--Navigation Panel--> <A NAME="tex2html3464" HREF="node68.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> <A NAME="tex2html3458" HREF="node30.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> <A NAME="tex2html3452" HREF="node66.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> <A NAME="tex2html3460" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> <A NAME="tex2html3462" HREF="node255.html"> <IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="index.png"></A> <BR> <B> Next:</B> <A NAME="tex2html3465" HREF="node68.html">4.15.1 Categorical CPT files</A> <B> Up:</B> <A NAME="tex2html3459" HREF="node30.html">4. General features</A> <B> Previous:</B> <A NAME="tex2html3453" HREF="node66.html">4.14 Specifying area fill</A> <B> <A NAME="tex2html3461" HREF="node1.html">Contents</A></B> <B> <A NAME="tex2html3463" HREF="node255.html">Index</A></B> <!--End of Navigation Panel--> <ADDRESS> Paul Wessel 2010-01-14 </ADDRESS> </BODY> </HTML>
