<!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>6.1.2 Equidistant conic projection (-Jd -JD)</TITLE> <META NAME="description" CONTENT="6.1.2 Equidistant conic projection (-Jd -JD)"> <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="node89.html"> <LINK REL="previous" HREF="node87.html"> <LINK REL="up" HREF="node86.html"> <LINK REL="next" HREF="node89.html"> </HEAD> <BODY bgcolor="#ffffff"> <!--Navigation Panel--> <A NAME="tex2html3840" HREF="node89.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> <A NAME="tex2html3834" HREF="node86.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> <A NAME="tex2html3828" HREF="node87.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> <A NAME="tex2html3836" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> <A NAME="tex2html3838" HREF="node256.html"> <IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="index.png"></A> <BR> <B> Next:</B> <A NAME="tex2html3841" HREF="node89.html">6.1.3 Lambert conic conformal</A> <B> Up:</B> <A NAME="tex2html3835" HREF="node86.html">6.1 Conic projections</A> <B> Previous:</B> <A NAME="tex2html3829" HREF="node87.html">6.1.1 Albers conic equal-area</A> <B> <A NAME="tex2html3837" HREF="node1.html">Contents</A></B> <B> <A NAME="tex2html3839" HREF="node256.html">Index</A></B> <BR> <BR> <!--End of Navigation Panel--> <H2><A NAME="SECTION001412000000000000000"> 6.1.2 Equidistant conic projection (<B>-Jd</B> <B>-JD</B>)</A> </H2> <A NAME="22421"></A> <A NAME="22422"></A> <A NAME="22423"></A> <P> The equidistant conic projection was described by the Greek philosopher Claudius Ptolemy about A.D. 150. It is neither conformal or equal-area, but serves as a compromise between them. The scale is true along all meridians and the standard parallels. To select this projection in <A NAME="tex2html1270" HREF="http://gmt.soest.hawaii.edu"><B>GMT</B></A> you must provide the same information as for the other conic projection, i.e. <P> <UL> <LI>Longitude and latitude of the projection center. </LI> <LI>Two standard parallels. </LI> <LI>Map scale in inch/degree or 1:xxxxx notation (<B>-Jd</B>), or map width (<B>-JD</B>). </LI> </UL> <P> The equidistant conic projection is often used for atlases with maps of small countries. As an example, we generate a map of Cuba: <P> <BR CLEAR="ALL"> <HR> <BR> <PRE>gmtset PLOT_DEGREE_FORMAT ddd:mm:ssF GRID_CROSS_SIZE_PRIMARY 0.05i pscoast -R-88/-70/18/24 -JD-79/21/19/23/4.5i -B5g1 -Di -N1/thick -Glightgray \ -Wthinnest -P > GMT_equidistant_conic.ps </PRE> <BR CLEAR="ALL"> <HR> <P> <DIV ALIGN="CENTER"><A NAME="fig:GMT_equidistant_conic"></A><A NAME="22677"></A> <TABLE> <CAPTION ALIGN="BOTTOM"><STRONG>Figure 6.2:</STRONG> Equidistant conic map projection</CAPTION> <TR><TD> <DIV ALIGN="CENTER"><IMG WIDTH="614" HEIGHT="248" ALIGN="BOTTOM" BORDER="0" SRC="img123.png" ALT="\includegraphics{scripts/GMT_equidistant_conic}"></DIV></TD></TR> </TABLE> </DIV> <P> <A NAME="22424"></A> <A NAME="22425"></A> <A NAME="22426"></A> <P> <HR> <!--Navigation Panel--> <A NAME="tex2html3840" HREF="node89.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> <A NAME="tex2html3834" HREF="node86.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> <A NAME="tex2html3828" HREF="node87.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> <A NAME="tex2html3836" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> <A NAME="tex2html3838" HREF="node256.html"> <IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="index.png"></A> <BR> <B> Next:</B> <A NAME="tex2html3841" HREF="node89.html">6.1.3 Lambert conic conformal</A> <B> Up:</B> <A NAME="tex2html3835" HREF="node86.html">6.1 Conic projections</A> <B> Previous:</B> <A NAME="tex2html3829" HREF="node87.html">6.1.1 Albers conic equal-area</A> <B> <A NAME="tex2html3837" HREF="node1.html">Contents</A></B> <B> <A NAME="tex2html3839" HREF="node256.html">Index</A></B> <!--End of Navigation Panel--> <ADDRESS> Paul Wessel 2010-07-14 </ADDRESS> </BODY> </HTML>