PSBASEMAP

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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