Geography Reference
In-Depth Information
• Lambert Azimuthal Equal Area
• Stereographic Equal Angle
• Orthographic
• Azimuthal Equidistant
• Gnomonic
• Mercator
• Transverse Mercator
• Universal Transverse Mercator
• Oblique Mercator
• Cassini Cylindrical
• Cylindrical Equidistant
• General Cylindrical
• Miller Cylindrical
• Miscellaneous
Each projection has a specific argument that must be supplied to the
-J
switch. Looking back at the globe example, you'll see that
-JA
was
used to specify the Lambert Azimuthal Equal Area projection. I know
because the programs that make up GMT provide a complete descrip-
tion of what's expected as input when you run them with no options.
For example, if we enter the
pscoast
command, we get several screens
of options and switches. The first part contains the available projection
switches and their syntax:
$
pscoast
pscoast 3.4.5 - Plot continents, shorelines, rivers, and borders on maps
usage: pscoast -J<params> -R<west>/<east>/<south>/<north>
[-A<min_area>[/<min_level>/<max_level>]] [-B<tickinfo>] [-C[<fill>]]
[-D<resolution>] [-Eaz/el] [-G[<fill>]]
[-I<feature>[/<pen>]] [-K]
[-L[f][x]<lon0>/<lat0>/<slat>/<length>[m|n|k]]
[-M[<flag>]] [-N<feature>[/<pen>]] [-O]
[-P] [-Q] [-S<fill>]
[-U[dx/dy/][label]] [-V]
[-W[<pen>]] [-X<x_shift>]
[-Y<y_shift>] [-bo[s][<n>]]
[-c<ncopies>]
-J Selects map proJection. (<scale> in cm/degree, <mapwidth> in cm)
-Ja|A<lon0>/<lat0>/<scale (or radius/lat)|mapwidth> (Lambert Azimuthal
Equal Area)
-Jb|B<lon0>/<lat0>/<lat1>/<lat2>/<scale|mapwidth> (Albers Equal-Area
Conic)
-Jc|C<lon0>/<lat0><scale|mapwidth> (Cassini)
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