PSBASEMAP
Section: Misc. Reference Manual Pages (l)
Updated: DATE
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#ifdef SI
#define UNIT cm
#define LEN_1 25
#define LEN_2 15
#define SCALE_LL -JX25l/15l
#define LEN_P 8
#define SCALE_P -JP16
#define LEN_C 10
#define LEN_M 0.064
#define POS_M 3/3
#define SCALE_M -Jm0.064
#define MAP_M -Lx3/3/0/5000
#define SCALE_O -Joc0/0/90/30/0.064d
#define LEN_Y 25
#define LEN_B 0.25
#define LEN_L 0.25
#define LEN_A 15
#define LEN_E 15
#define LEN_G 15
#define LEN_S 12
#define SCALE_S -Js0/-90/12/-60
#define LEN_I 0.05
#define LEN_K 0.064
#define LEN_N 20
#define LEN_R 25
#define LEN_W 25
#else
#define UNIT inch
#define LEN_1 9
#define LEN_2 6
#define SCALE_LL -JX9l/6l
#define LEN_P 3
#define SCALE_P -JP6
#define LEN_C 4
#define LEN_M 0.025
#define POS_M 1/1
#define SCALE_M -Jm0.025
#define MAP_M -Lx1/1/0/5000
#define SCALE_O -Joc0/0/90/30/0.025d
#define LEN_Y 9
#define LEN_B 0.1
#define LEN_L 0.1
#define LEN_A 6
#define LEN_E 6
#define LEN_G 6
#define LEN_S 5
#define SCALE_S -Js0/-90/5/-60
#define LEN_I 0.02
#define LEN_K 0.025
#define LEN_N 8
#define LEN_R 9
#define LEN_W 10
#endif
NAME
psbasemap - To plot PostScript basemaps
SYNOPSIS
psbasemap -Btickinfo -Jparameters -Rwest/east/south/north[r]
[ -Eazimuth/elevation ] [ -Fred/green/blue ] [ -Gfill ] [ -K ]
[ -L[f][x]lon0/lat0/slat/length[m] ] [ -O ]
[ -P ] [ -U[/dx/dy/][label] ]
[ -V ] [ -Xx-shift ] [ -Yy-shift ] [ -Xy-level ] [ -Zzlevel ] [ -ccopies ]
DESCRIPTION
psbasemap creates PostScript code that will produce a basemap. Several map projections
are available, and the user may specify separate tickmark intervals for boundary annotation,
ticking, and [optionally] gridlines. A simple map scale may also be plotted.
No space between the option flag and the associated arguments. Use upper case for the
option flags and lower case for modifiers.
#include "explain_-B.txt"
#include "explain_-J.txt"
#include "explain_-R.txt"
OPTIONS
- -E
-
Sets the viewpoint's azimuth and elevation (for perspective view) [180/90]
- -F
-
Sets the color used for Frame and annotation. [Default is 0/0/0 (black)]
- -G
-
Sets a color or pattern with which to paint inside of basemap. [Default is no fill]
#include "explain_-Jz.txt"
#include "explain_-K.txt"
- -L
-
Draws a simple map scale centered on lon0/lat0. Use -Lx to specify position in UNIT instead.
Scale is calculated at latitude slat, length is in km [miles if m is appended].
Use -Lf to get a "fancy" scale [Default is plain].
#include "explain_-O.txt"
#include "explain_-P.txt"
#include "explain_-U.txt"
#include "explain_-V.txt"
#include "explain_-XY.txt"
- -Z
-
For 3-D projections: Sets the z-level of the basemap [0].
#include "explain_-c.txt"
EXAMPLES
The following section illustrates the use of the options by giving some examples for the
available map projections. Note how scales may be given in several different ways
depending on the projection. Also note the use of upper case letters to specify map width in UNIT
instead of map scale.
NON-GEOGRAPHICAL PROJECTIONS
Linear x-y plot
To make a linear x/y frame with all axes, but with only left and bottom axes annotated, using xscale = yscale = 1.0,
ticking every 1 unit and annotating every 2, and using xlabel = "Distance" and ylabel = "No of samples", try
psbasemap -R0/9/0/5 -Jx1 -Bf1a2:Distance:/:"No of samples":WeSn > linear.ps
log-log plot
To make a log-log frame with only the left and bottom axes, where the x-axis is LEN_1 UNIT and annotated
every 1-2-5 and the y-axis is LEN_2 UNIT and anotated every power of 10 but has tickmarks every 0.1, try
psbasemap -R1/10000/1e20/1e25 SCALE_LL -B2:Wavelength:/a1pf3:Power:WS > loglog.ps
power axes
To design an axis system to be used for a depth-sqrt(age) plot with depth positive down, ticked and
annotated every 500m, and ages annotated at 1 my, 4 my, 9 my etc, try
psbasemap -R0/100/0/5000 -Jx1p0.5/-0.001 -B1p:"Crustal age":/500:Depth: > power.ps
Polar (theta,r) plot
For a base map for use with polar coordinates, where the radius from 0 to 1000 should correspond
to LEN_P UNIT, and with gridlines and ticks every 30 degrees and 100 units, try
psbasemap -R0/360/0/1000 SCALE_P -B30p/100 > polar.ps
CYLINDRICAL MAP PROJECTIONS
Cassini
A LEN_C-UNIT-wide basemap using the Cassini projection may be obtained by
psbasemap -R20/50/20/35 -JC35/28/LEN_C -P -B5g5:.Cassini: > cassini.ps
Mercator [conformal]
A Mercator map with scale LEN_M UNIT/degree along equator, and showing the length of 5000 km along the equator (centered on POS_M UNIT), may be plotted as
psbasemap -R90/180/-50/50 SCALE_M -B30g30:.Mercator: MAP_M > mercator.ps
Oblique Mercator [conformal]
To create a page-size global oblique Mercator basemap for a pole at (90,30) with gridlines every 30 degrees, try
psbasemap -R0/360/-70/70 SCALE_O -B30g30:."Oblique Mercator": > oblmerc.ps
Transverse Mercator [conformal]
A regular Transverse Mercator basemap for some region may look like
psbasemap -R69:30/71:45/-17/-15:15 -Jt70/1:1000000 -B15m:."Survey area": -P > transmerc.ps
Equidistant Cylindrical Projection
This projection only needs the central meridian and scale. A LEN_Y UNIT wide global basemap centered on the 130E
meridian is made by
psbasemap -R-50/310/-90/90 -JQ130/LEN_Y -B30g30:."Equidistant Cylindrical": > cyl_eqdist.ps
Universal Transverse Mercator [conformal]
To use this projection you must know the UTM zone number, which defines the central meridian. A UTM
basemap for Indo-China can be plotted as
psbasemap -R95/5/108/20r -Ju46/1:10000000 -B3g3:.UTM: > utm.ps
Basic Cylindrical [equal-area]
First select which of the cylindrical equal-area projections you want by deciding on the standard parallel.
Here we will use 45 degrees which gives the Peters projection. A LEN_Y UNIT wide global basemap centered on the Pacific
is made by
psbasemap -R0/360/-90/90 -JY180/45/LEN_Y -B30g30:.Peters: > peters.ps
CONIC MAP PROJECTIONS
Albers [equal-area]
A basemap for middle Europe may be created by
psbasemap -R0/90/25/55 -Jb45/20/32/45/LEN_B -B10g10:."Albers Equal-area": > albers.ps
Lambert [conformal]
Another basemap for middle Europe may be created by
psbasemap -R0/90/25/55 -Jl45/25/32/45/LEN_L -B10g10:."Lambert Conformal Conic": > lambertc.ps
AZIMUTHAL MAP PROJECTIONS
Lambert [equal-area]
A LEN_A-UNIT-wide global view of the world from the vantage point -80/-30 will give the following basemap:
psbasemap -R0/360-/-90/90 -JA-80/-30/LEN_A -B30g30/15g15:."Lambert Azimuthal": > lamberta.ps
Follow the instructions for stereographic projection if you want to impose rectangular
boundaries on the azimuthal equal-area map but substitute -Ja for -Js.
Equidistant
A LEN_E-UNIT-wide global map in which distances from the center (here 125/10) to any point is true can be obtained by:
psbasemap -R0/360-/-90/90 -JE125/10/LEN_E -B30g30/15g15:."Equidistant": > equi.ps
Orthographic
A global perspective (from infinite distance) view of the world from the vantage point -100/40 will give the following LEN_G-UNIT-wide basemap:
psbasemap -R0/360-/-90/90 -JG125/10/LEN_G -B30g30/15g15:."Orthographic": > ortho.ps
Stereographic [conformal]
To make a Polar stereographic projection basemap with radius = LEN_S UNIT to -60 degree latitude, with plot title
"Salinity measurements", using 5 degrees annotation/tick interval and 1 degree gridlines, try
psbasemap -R-45/45/-90/-60 SCALE_S -B5g1:."Salinity measurements": > stereo1.ps
To make a LEN_S-UNIT-wide stereographic basemap for Australia from an arbitrary view point (not the poles), and use a
rectangular boundary, we must give the pole for the new projection and use the -R option to
indicate the lower left and upper right corners (in lon/lat) that will define our rectangle. We
choose a pole at 130/-30 and use 100/-45 and 160/-5 as our corners. The command becomes
psbasemap -R100/-45/160/-5r -JS130/-30/LEN_S -B30g30/15g15:."General Stereographic View": > stereo2.ps
MISCELLANEOUS MAP PROJECTIONS
Hammer [equal-aera]
The Hammer projection is mostly used for global maps and thus the spherical form is used.
To get a world map centered on Greenwich at a scale of 1:200000000, try
psbasemap -R0/360/-90/90 -Jh180/1:200000000 -B30g30/15g15:.Hammer: > hammer.ps
Sinusoidal [equal-aera]
To make a sinusiodal world map centered on Greenwich, with a scale along the equator of LEN_I UNIT/degree, try
psbasemap -R0/360/-90/90 -Ji0/LEN_I -B30g30/15g15:."Sinusoidal": > sinus1.ps
To make an interrupted sinusiodal world map with breaks at 160W, 20W, and 60E, with a scale along the equator of LEN_I UNIT/degree, try the following sequence of commands:
psbasemap -R-160/-20/-90/90 -Ji-90/LEN_I -B30g30/15g15Wesn -K > sinus_i.ps
psbasemap -R-20/60/-90/90 -Ji20/LEN_I -B30g30/15g15wesn -O -K -X2.8 >> sinus_i.ps
psbasemap -R60/200/-90/90 -Ji130/LEN_I -B30g30/15g15wEsn -O -X1.6 >> sinus_i.ps
Eckert VI [equal-aera]
Another pseudo-cylindrical projection typically used for global maps only. Set the central longitude and scale, e.g.,
psbasemap -R0/360/-90/90 -Jk180/LEN_K -B30g30/15g15:."Eckert VI": > eckert4.ps
Robinson
Projection designed to make global maps "look right". Set the central longitude and width, e.g.,
psbasemap -R-180/180/-90/90 -JN0/LEN_N -B30g30/15g15:."Robinson": > robinson.ps
Winkel Tripel
Yet another projection typically used for global maps only. You can set the central longitude, e.g.,
psbasemap -R90/450/-90/90 -JR270/LEN_R -B30g30/15g15:."Winkel Tripel": > winkel.ps
Mollweide [equal-aera]
The Mollweide projection is also mostly used for global maps and thus the spherical form is used.
To get a LEN_W-UNIT-wide world map centered on the Dateline, try
psbasemap -R0/360/-90/90 -JW180/LEN_W -B30g30/15g15:.Mollweide: > mollweide.ps
RESTRICTIONS
For some projections, a spherical earth is implicitly assumed. A warning will notify the user if -V
is set.
BUGS
The -B option is somewhat complicated to explain and comprehend. However, it is fairly simple for
most applications (see examples).
SEE ALSO
gmtdefaults, gmt
#include "refs.i"
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- OPTIONS
-
- EXAMPLES
-
- NON-GEOGRAPHICAL PROJECTIONS
-
- Linear x-y plot
-
- log-log plot
-
- power axes
-
- Polar (theta,r) plot
-
- CYLINDRICAL MAP PROJECTIONS
-
- Cassini
-
- Mercator [conformal]
-
- Oblique Mercator [conformal]
-
- Transverse Mercator [conformal]
-
- Equidistant Cylindrical Projection
-
- Universal Transverse Mercator [conformal]
-
- Basic Cylindrical [equal-area]
-
- CONIC MAP PROJECTIONS
-
- Albers [equal-area]
-
- Lambert [conformal]
-
- AZIMUTHAL MAP PROJECTIONS
-
- Lambert [equal-area]
-
- Equidistant
-
- Orthographic
-
- Stereographic [conformal]
-
- MISCELLANEOUS MAP PROJECTIONS
-
- Hammer [equal-aera]
-
- Sinusoidal [equal-aera]
-
- Eckert VI [equal-aera]
-
- Robinson
-
- Winkel Tripel
-
- Mollweide [equal-aera]
-
- RESTRICTIONS
-
- BUGS
-
- SEE ALSO
-
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Time: 07:11:12 GMT, January 07, 2025