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# psbasemap

psbasemap - Plot PostScript base maps

## Synopsis

psbasemap -Jparameters -Rwest/east/south/north[/zmin/zmax][r] [ -B[p|s]parameters ] [ -D[unit]xmin/xmax/ymin/ymax[r]|width[/height][+cclon/clat][+ppen][+gfill]] [ -K ] [ -Jz|Zparameters ] -L[f][x]lon0/lat0[/slon]/slat/length[e|f|k|M|n|u][+llabel][+jjust][+ppen][+gfill][+u] ] ] [ -O ] [ -P ] [ -U[just/dx/dy/][c|label] ] [ -T[f|m][x]lon0/lat0/size[/info][:w,e,s,n:][+gint[/mint]] ] [ -V[level] ] [ -X[a|c|f|r][x-shift[u]] ] [ -Y[a|c|f|r][y-shift[u]] ] [ -ccopies ] [ -f[i|o]colinfo ] [ -p[x|y|z]azim/elev[/zlevel][+wlon0/lat0[/z0]][+vx0/y0] ] [ -t[transp] ]

Note: No space is allowed between the option flag and the associated arguments.

## 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 or directional rose may also be plotted. At least one of the options -B, -L[f][x]lon0/lat0[/slon]/slat/length[e|f|k|M|n|u][+llabel][+jjust][+ppen][+gfill][+u], or -T[f|m][x]lon0/lat0/size[/info][:w,e,s,n:][+gint[/mint]] must be specified.

## Required Arguments

-Jparameters (more ...)
  Select map projection.

-R[unit]xmin/xmax/ymin/ymax[r] (more ...)
  Specify the region of interest.

For perspective view p, optionally append /zmin/zmax. (more ...)

## Optional Arguments

-B[p|s]parameters (more ...)
  Set map boundary intervals.
-D[unit]xmin/xmax/ymin/ymax[r]|width[/height][+cclon/clat][+ppen][+gfill]
  Draw a simple map insert box on the map. Specify the box in one of three ways: (a) Give west/east/south/north of geographic rectangle bounded by parallels and meridians; append r if the coordinates instead are the lower left and upper right corners of the desired rectangle. (b) Give uxmin/xmax/ymin/ymax of bounding rectangle in projected coordinates (here, u is the coordinate unit). (c) Give [u]width[/height] of bounding rectangle and use +c to set box center. Append any combination of the following modifiers to draw the insert box: +clon/lat to specify box center. +gfill to paint a insert [no fill]. +ppen to draw the insert outline [no outline].

-Jz|Zparameters (more ...)
  Set z-axis scaling; same syntax as -Jx.

-K (more ...)
  Do not finalize the PostScript plot.

-L[f][x]lon0/lat0[/slon]/slat/length[e|f|k|M|n|u][+llabel][+jjust][+ppen][+gfill][+u]
  Draws a simple map scale centered on lon0/lat0. Use -Lx to specify x/y position instead. Scale is calculated at latitude slat (optionally supply longitude slon for oblique projections [Default is central meridian]), length is in km, or append unit from e|f|k|M|n|u. Use -Lf to get a “fancy” scale [Default is plain]. Append +l to select the default label which equals the distance unit (meter, foot, km, mile, nautical mile, US survey foot) and is justified on top of the scale [t]. Change this by giving your own label (append +llabel). Change label justification with +jjustification (choose among l(eft), r(ight), t(op), and b(ottom)). Apply +u to append the unit to all distance annotations along the scale. If you want to place a rectangle behind the scale, specify suitable +ppen and/or +gfill parameters. Note: Use FONT_LABEL to change the label font and FONT_ANNOT_PRIMARY to change the annotation font. The height of the map scale is controlled by MAP_SCALE_HEIGHT.

-O (more ...)
  Append to existing PostScript plot.

-P (more ...)
  Select “Portrait” plot orientation.

-T[f|m][x]lon0/lat0/size[/info][:w,e,s,n:][+gint[/mint]]
  Draws a simple map directional rose centered on lon0/lat0. Use -Tx to specify x/y position instead. The size is the diameter of the rose, and optional label information can be specified to override the default values of W, E, S, and N (Give :: to suppress all labels). The default [plain] map rose only labels north. Use -Tf to get a “fancy” rose, and specify in info what you want drawn. The default [1] draws the two principal E-W, N-S orientations, 2 adds the two intermediate NW-SE and NE-SW orientations, while 3 adds the eight minor orientations WNW-ESE, NNW-SSE, NNE-SSW, and ENE-WSW. For a magnetic compass rose, specify -Tm. If given, info must be the two parameters dec/dlabel, where dec is the magnetic declination and dlabel is a label for the magnetic compass needle (specify - to format a label from dec). Then, both directions to geographic and magnetic north are plotted [Default is geographic only]. If the north label is * then a north star is plotted instead of the north label. Annotation and two levels of tick intervals for both geographic and magnetic directions are 30/5/1 degrees; override these settings by appending +gints[/mints]. Color and pen attributes for the rose are taken from COLOR_BACKGROUND and MAP_TICK_PEN, respectively, while label fonts, colors and sizes follow FONT_TITLE for the four major directions and FONT_LABEL for minor directions.

-U[just/dx/dy/][c|label] (more ...)
  Draw GMT time stamp logo on plot.

-V[level] (more ...)
  Select verbosity level [c].

-X[a|c|f|r][x-shift[u]]

-Y[a|c|f|r][y-shift[u]] (more ...)
  Shift plot origin.

-ccopies (more ...)
  Specify number of plot copies [Default is 1].

-f[i|o]colinfo (more ...)
  Specify data types of input and/or output columns. This applies only to the coordinates specified in the -R option.

-p[x|y|z]azim/elev[/zlevel][+wlon0/lat0[/z0]][+vx0/y0] (more ...)
  Select perspective view.

-t[transp] (more ...)
  Set PDF transparency level in percent.

-^
  Print a short message about the syntax of the command, then exits (NOTE: on Windows use just -).
+
  Print an extensive usage (help) message, including the explanation of any module-specific option (but not the GMT common options), then exits.
-?
  Print a complete usage (help) message, including the explanation of options, then exits.
--version
  Print GMT version and exit.
--show-datadir
  Print full path to GMT share directory and exit.

## 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 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”, use

>     gmt 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 25 cm and annotated every 1-2-5 and the y-axis is 15 cm and annotated every power of 10 but has tickmarks every 0.1, run

>     gmt psbasemap -R1/10000/1e20/1e25 -JX25cl/15cl -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, use

>     gmt 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 3 inch and with gridlines and ticks every 30 degrees and 100 units, use

>     gmt psbasemap -R0/360/0/1000 -JP6i -B30p/100 > polar.ps

## Cylindrical Map Projections

### Cassini

A 10-cm-wide basemap using the Cassini projection may be obtained by

>     gmt psbasemap -R20/50/20/35 -JC35/28/10c -P -B5g5:.Cassini: > cassini.ps

### Mercator [conformal]

A Mercator map with scale 0.025 inch/degree along equator, and showing the length of 5000 km along the equator (centered on 1/1 inch), may be plotted as

>     gmt psbasemap -R90/180/-50/50 -Jm0.025i -B30g30:.Mercator: -Lx1i/1i/0/5000 > mercator.ps

### Miller

A global Miller cylindrical map with scale 1:200,000,000 may be plotted as

>     gmt psbasemap -Rg -Jj180/1:200000000 -B30g30:.Miller: > miller.ps

### Oblique Mercator [conformal]

To create a page-size global oblique Mercator basemap for a pole at (90,30) with gridlines every 30 degrees, run

>     gmt psbasemap -R0/360/-70/70 -Joc0/0/90/30/0.064cd -B30g30:."Oblique Mercator": > oblmerc.ps

### Transverse Mercator [conformal]

A regular Transverse Mercator basemap for some region may look like

>     gmt 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 25 cm wide global basemap centered on the 130E meridian is made by

>     gmt psbasemap -R-50/310/-90/90 -JQ130/25c -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

>     gmt psbasemap -R95/5/108/20r -Ju46/1:10000000 -B3g3:.UTM: > utm.ps

### 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 Gall-Peters projection. A 9 inch wide global basemap centered on the Pacific is made by

>     gmt psbasemap -Rg -JY180/45/9i -B30g30:.Gall-Peters: > gall-peters.ps

## Conic Map Projections

### Albers [equal-area]

A basemap for middle Europe may be created by

>     gmt psbasemap -R0/90/25/55 -Jb45/20/32/45/0.25c -B10g10:."Albers Equal-area": > albers.ps

### Lambert [conformal]

Another basemap for middle Europe may be created by

>     gmt psbasemap -R0/90/25/55 -Jl45/20/32/45/0.1i -B10g10:."Lambert Conformal Conic": > lambertc.ps

### Equidistant

Yet another basemap of width 6 inch for middle Europe may be created by

>     gmt psbasemap -R0/90/25/55 -JD45/20/32/45/6i -B10g10:."Equidistant conic": > econic.ps

### Polyconic

A basemap for north America may be created by

>     gmt psbasemap -R-180/-20/0/90 -JPoly/4i -B30g10/10g10:."Polyconic": > polyconic.ps

## Azimuthal Map Projections

### Lambert [equal-area]

A 15-cm-wide global view of the world from the vantage point -80/-30 will give the following basemap:

>     gmt psbasemap -Rg -JA-80/-30/15c -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 15-cm-wide global map in which distances from the center (here 125/10) to any point is true can be obtained by:

>     gmt psbasemap -Rg -JE125/10/15c -B30g30/15g15:.Equidistant: > equi.ps

### Gnomonic

A view of the world from the vantage point -100/40 out to a horizon of 60 degrees from the center can be made using the Gnomonic projection:

>     gmt psbasemap -Rg -JF-100/40/60/6i -B30g30/15g15:.Gnomonic: > gnomonic.ps

### Orthographic

A global perspective (from infinite distance) view of the world from the vantage point 125/10 will give the following 6-inch-wide basemap:

>     gmt psbasemap -Rg -JG125/10/6i -B30g30/15g15:.Orthographic: > ortho.ps

### General Perspective

The -JG option can be used in a more generalized form, specifying altitude above the surface, width and height of the view point, and twist and tilt. A view from 160 km above -74/41.5 with a tilt of 55 and azimuth of 210 degrees, and limiting the viewpoint to 30 degrees width and height will product a 6-inch-wide basemap:

>     gmt psbasemap -Rg -JG-74/41.5/160/210/55/30/30/6i -B5g1/5g1:."General Perspective": > genper.ps

### Stereographic [conformal]

To make a polar stereographic projection basemap with radius = 12 cm to -60 degree latitude, with plot title “Salinity measurements”, using 5 degrees annotation/tick interval and 1 degree gridlines, run

>     gmt psbasemap -R-45/45/-90/-60 -Js0/-90/12c/-60 -B5g5:."Salinity measurements": > stereo1.ps

To make a 12-cm-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

>     gmt psbasemap -R100/-45/160/-5r -JS130/-30/12c -B30g30/15g15:."General Stereographic View": > stereo2.ps

## Miscellaneous Map Projections

### Hammer [equal-area]

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, use

>     gmt psbasemap -Rd -Jh0/1:200000000 -B30g30/15g15:.Hammer: > hammer.ps

### Sinusoidal [equal-area]

To make a sinusoidal world map centered on Greenwich, with a scale along the equator of 0.02 inch/degree, use

>     gmt psbasemap -Rd -Ji0/0.02i -B30g30/15g15:.Sinusoidal: > sinus1.ps

To make an interrupted sinusoidal world map with breaks at 160W, 20W, and 60E, with a scale along the equator of 0.02 inch/degree, run the following sequence of commands:

>     gmt psbasemap -R-160/-20/-90/90 -Ji-90/0.02i -B30g30/15g15Wesn -K > sinus_i.ps
>     gmt psbasemap -R-20/60/-90/90 -Ji20/0.02i -B30g30/15g15wesn -O -K -X2.8i >> sinus_i.ps
>     gmt psbasemap -R60/200/-90/90 -Ji130/0.02i -B30g30/15g15wEsn -O -X1.6i >> sinus_i.ps

### Eckert IV [equal-area]

Pseudo-cylindrical projection typically used for global maps only. Set the central longitude and scale, e.g.,

>     gmt psbasemap -Rg -Jkf180/0.064c -B30g30/15g15:."Eckert IV": > eckert4.ps

### Eckert VI [equal-area]

Another pseudo-cylindrical projection typically used for global maps only. Set the central longitude and scale, e.g.,

>     gmt psbasemap -Rg -Jks180/0.064c -B30g30/15g15:."Eckert VI": > eckert6.ps

### Robinson

Projection designed to make global maps “look right”. Set the central longitude and width, e.g.,

>     gmt psbasemap -Rd -JN0/8i -B30g30/15g15:.Robinson: > robinson.ps

### Winkel Tripel

Yet another projection typically used for global maps only. You can set the central longitude, e.g.,

>     gmt psbasemap -R90/450/-90/90 -JR270/25c -B30g30/15g15:."Winkel Tripel": > winkel.ps

### Mollweide [equal-area]

The Mollweide projection is also mostly used for global maps and thus the spherical form is used. To get a 25-cm-wide world map centered on the Dateline:

>     psbasemap -Rg -JW180/25c -B30g30/15g15:.Mollweide: > mollweide.ps

### Van der Grinten

The Van der Grinten projection is also mostly used for global maps and thus the spherical form is used. To get a 7-inch-wide world map centered on the Dateline:

>     gmt psbasemap -Rg -JV180/7i -B30g30/15g15:."Van der Grinten": > grinten.ps

## CUSTOM lABELS OR INTERVALS

The -B option sets up a regular annotation interval and the annotations derive from the corresponding x, y, or z coordinates. However, some applications requires special control on which annotations to plot and even replace the annotation with other labels. This is achieved by using cintfile in the -B option, where intfile contains all the information about annotations, ticks, and even gridlines. Each record is of the form coord type [label], where coord is the coordinate for this annotation (or tick or gridline), type is one or more letters from a (annotation), i interval annotation, f tickamrk, and g gridline. Note that a and i are mutually exclusive and cannot both appear in the same intfile. Both a and i requires you to supply a label which is used as the plot annotation. If not given then a regular formatted annotation based on the coordinate will occur.

## 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

gmt, gmt.conf, gmtcolors

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