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Next: Stereographic Equal-Angle Projection (-–Js Up: Lambert Azimuthal Equal-Area (-–Ja Previous: Rectangular map

   
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





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 0o/0o) 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
1999-07-01