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Next: 5.3.2 Stereographic Equal-Angle Projection Up: 5.3.1 Lambert Azimuthal Equal-Area Previous: 5.3.1.1 Rectangular map   Contents   Index


5.3.1.2 Hemisphere map

Here, you must specify the world as your region (-R0/360/-90/90). E. g., to obtain a hemisphere view that shows the Americas, try





#!/bin/sh
#    $Id: GMT_lambert_az_hemi.sh,v 1.1 2001/03/21 04:10:21 pwessel Exp $
#

pscoast -R0/360/-90/90 -JA280/30/3.5i -B30g30/15g15 -Dc -A1000 -G0 -P > GMT_lambert_az_hemi.ps





Figure 5.10: Hemisphere map using the Lambert azimuthal equal-area projection.
\begin{figure}\centering\epsfig{figure=eps/GMT_lambert_az_hemi.eps}\end{figure}

To geologists, the Lambert azimuthal equal-area projection (with origin at 0$^{o}$/0$^{o}$) is known as the equal-area (Schmidt) stereonet and used for plotting fold axes, fault planes, and the like. An equal-angle (Wulff) stereonet can be obtained by using the stereographic projection (discussed later). The stereonets produced by these two projections appear below.

Figure 5.11: Equal-Area (Schmidt) and Equal-Angle (Wulff) stereo nets
\begin{figure}\centering\epsfig{figure=eps/GMT_stereonets.eps}\end{figure}



Paul Wessel 2001-04-18