PSBASEMAP(1) Generic Mapping Tools PSBASEMAP(1)NAMEpsbasemap - To plot PostScript basemaps
SYNOPSISpsbasemap -B[p|s]parameters -Jparameters
-Rwest/east/south/north[/zmin/zmax][r] [
-Eazim/elev[+wlon/lat[/z]][+vx0/y0] ] [ -Gfill ] [ -Jz|Zparameters ] [
-K ] [ -L[f][x]lon0/lat0[/slon]/slat/length[m|n|k][+lla‐
bel][+jjust][+ppen][+ffill][+u] ] ] [ -O ] [ -P ] [
-U[just/dx/dy/][c|label] ] [
-T[f|m][x]lon0/lat0/size[/info][:w,e,s,n:][+gint[/mint]] ] [ -V ] [
-X[a|c|r][x-shift[u]] ] [ -Y[a|c|r][y-shift[u]] ] [ -Zzlevel ] [
-ccopies ]
DESCRIPTIONpsbasemap creates PostScript code that will produce a basemap. Several
map projections are available, and the user may specify separate tick‐
mark intervals for boundary annotation, ticking, and [optionally] grid‐
lines. A simple map scale or directional rose may also be plotted.
-B Sets map boundary annotation and tickmark intervals. The format
of tickinfo is
[p|s]xinfo[/yinfo[/zinfo]][:."Title":][W|w][E|e][S|s][N|n][Z|z[+]].
The leading p [Default] or s selects the primary or secondary
annotation information. Each of the ?info segments are
textstrings of the form info[:"Axis label":][:="pre‐
fix":][:,"unit label":]. The info string is made up of one or
more concatenated substrings of the form
[a|f|g]stride[+-phase][unit]. The leading a is used to specify
the annotation and major tick spacing [Default], f for minor
tick spacing, and g for gridline spacing. stride is the desired
stride interval. The optional phase shifts the annotation
interval by that amount (positive or negative). The optional
unit indicates the unit of the stride and can be any of Y (year,
plot with 4 digits), y (year, plot with 2 digits), O (month,
plot using PLOT_DATE_FORMAT), o (month, plot with 2 digits), U
(ISO week, plot using PLOT_DATE_FORMAT), u (ISO week, plot using
2 digits), r (Gregorian week, 7-day stride from start of week
TIME_WEEK_START), K (ISO weekday, plot name of day), D (date,
plot using PLOT_DATE_FORMAT), d (day, plot day of month 0-31 or
year 1-366, via PLOT_DATE_FORMAT), R (day, same as d, aligned
with TIME_WEEK_START), H (hour, plot using PLOT_CLOCK_FORMAT), h
(hour, plot with 2 digits), M (minute, plot using
PLOT_CLOCK_FORMAT), m (minute, plot with 2 digits), C (second,
plot using PLOT_CLOCK_FORMAT), c (second, plot with 2 digits).
Note for geographic axes m and c instead mean arc minutes and
arc seconds. All entities that are language-specific are under
control by TIME_LANGUAGE. To specify separate x and y ticks,
separate the substrings that apply to the x and y axes with a
slash [/] (If a 3-D basemap is selected with -E and -Jz, a third
substring pertaining to the vertical axis may be appended.) For
linear/log/power projections (-Jx|X): Labels for each axis can
be added by surrounding them with colons (:). If the first
character in the label is a period, then the label is used as
plot title; if it is a comma (,) then the label is appended to
each annotation; if it is an equal sign (=) the the prefix is
prepended to each annotation (start label/prefix with - to avoid
space between annotation and item); else it is the axis label.
If the label consists of more than one word, enclose the entire
label in double quotes (e.g., :"my label":). If you need to use
a colon (:) as part of your label you must specify it using its
octal code (\072).
By default, all 4 boundaries are plotted (referred to as W, E,
S, N). To change the default, append the code for only those
axes you want (e.g., WS for standard lower-left x- and y-axis
system). Upper case (e.g., W) means draw axis/tickmarks AND
annotate it, whereas lower case (e.g., w) will only draw
axis/tickmarks. (If a 3-D basemap is selected with -E and -Jz,
append Z or z to control the appearance of the vertical axis.
Append + to draw the outline of the cube defined by -R. Note
that for 3-D views the title, if given, will be suppressed.)
For non-geographical projections: Give negative scale (in -Jx)
or axis length (in -JX) to change the direction of increasing
coordinates (i.e., to make the y-axis positive down). For log10
axes: Annotations can be specified in one of three ways: (1)
stride can be 1, 2, 3, or -n. Annotations will then occur at 1,
1-2-5, or 1-2-3-4-...-9, respectively; for -n we annotate every
n't magnitude. This option can also be used for the frame and
grid intervals. (2) An l is appended to the tickinfo string.
Then, log10 of the tick value is plotted at every integer log10
value. (3) A p is appended to the tickinfo string. Then, anno‐
tations appear as 10 raised to log10 of the tick value. For
power axes: Annotations can be specified in one of two ways:
(1) stride sets the regular annotation interval. (2) A p is
appended to the tickinfo string. Then, the annotation interval
is expected to be in transformed units, but the annotation value
will be plotted as untransformed units. E.g., if stride = 1 and
power = 0.5 (i.e., sqrt), then equidistant annotations labeled
1-4-9... will appear.
These GMT parameters can affect the appearance of the map bound‐
ary: ANNOT_MIN_ANGLE, ANNOT_MIN_SPACING, ANNOT_FONT_PRIMARY,
ANNOT_FONT_SECONDARY, ANNOT_FONT_SIZE_PRIMARY,
ANNOT_FONT_SIZE_SECONDARY, ANNOT_OFFSET_PRIMARY, ANNOT_OFF‐
SET_SECONDARY, BASEMAP_AXES, BASEMAP_FRAME_RGB, BASEMAP_TYPE,
PLOT_DEGREE_FORMAT, FRAME_PEN, FRAME_WIDTH, GRID_CROSS_SIZE_PRI‐
MARY, GRID_PEN_PRIMARY, GRID_CROSS_SIZE_SECONDARY, GRID_PEN_SEC‐
ONDARY, HEADER_FONT, HEADER_FONT_SIZE, LABEL_FONT,
LABEL_FONT_SIZE, LINE_STEP, OBLIQUE_ANNOTATION, PLOT_CLOCK_FOR‐
MAT, PLOT_DATE_FORMAT, TIME_FORMAT_PRIMARY, TIME_FORMAT_SEC‐
ONDARY, TIME_LANGUAGE, TIME_WEEK_START, TICK_LENGTH, TICK_PEN,
and Y_AXIS_TYPE; see the gmtdefaults man page for details.
-J Selects the map projection. The following character determines
the projection. If the character is upper case then the argu‐
ment(s) supplied as scale(s) is interpreted to be the map width
(or axis lengths), else the scale argument(s) is the map scale
(see its definition for each projection). UNIT is cm, inch, or
m, depending on the MEASURE_UNIT setting in .gmtdefaults4, but
this can be overridden on the command line by appending c, i, or
m to the scale or width values. Append h, +, or - to the given
width if you instead want to set map height, the maximum dimen‐
sion, or the minimum dimension, respectively [Default is w for
width].
In case the central meridian is an optional parameter and it is
being omitted, then the center of the longitude range given by
the -R option is used. The default standard parallel is the
equator.
The ellipsoid used in the map projections is user-definable by
editing the .gmtdefaults4 file in your home directory. 73 com‐
monly used ellipsoids and spheroids are currently supported, and
users may also specify their own custum ellipsoid parameters
[Default is WGS-84]. Several GMT parameters can affect the pro‐
jection: ELLIPSOID, INTERPOLANT, MAP_SCALE_FACTOR, and MEA‐
SURE_UNIT; see the gmtdefaults man page for details.
Choose one of the following projections (The E or C after pro‐
jection names stands for Equal-Area and Conformal, respec‐
tively):
CYLINDRICAL PROJECTIONS:
-Jclon0/lat0/scale or -JClon0/lat0/width (Cassini).
Give projection center lon0/lat0 and scale (1:xxxx or
UNIT/degree).
-Jcyl_stere/[lon0/[lat0/]]scale or
-JCyl_stere/[lon0/[lat0/]]width (Cylindrical Stereographic).
Give central meridian lon0 (optional), standard parallel
lat0 (optional), and scale along parallel (1:xxxx or
UNIT/degree). The standard parallel is typically one of
these (but can be any value):
66.159467 - Miller's modified Gall
55 - Kamenetskiy's First
45 - Gall's Stereographic
30 - Bolshoi Sovietskii Atlas Mira or Kamenet‐
skiy's Second
0 - Braun's Cylindrical
-Jj[lon0/]scale or -JJ[lon0/]width (Miller Cylindrical Projec‐
tion).
Give the central meridian lon0 (optional) and scale
(1:xxxx or UNIT/degree).
-Jm[lon0/[lat0/]]scale or -JM[lon0/[lat0/]]width
Give central meridian lon0 (optional), standard parallel
lat0 (optional), and scale along parallel (1:xxxx or
UNIT/degree).
-Joparameters (Oblique Mercator [C]).
Typically used with -R<...>r, otherwise region is in
oblique coordinates. Specify one of:
-Jo[a]lon0/lat0/azimuth/scale or
-JO[a]lon0/lat0/azimuth/width
Set projection center lon0/lat0, azimuth of
oblique equator, and scale.
-Jo[b]lon0/lat0/lon1/lat1/scale or
-JO[b]lon0/lat0/lon1/lat1/scale
Set projection center lon0/lat0, another point on
the oblique equator lon1/lat1, and scale.
-Joclon0/lat0/lonp/latp/scale or
-JOclon0/lat0/lonp/latp/scale
Set projection center lon0/lat0, pole of oblique
projection lonp/latp, and scale.
Give scale along oblique equator (1:xxxx or UNIT/degree).
-Jq[lon0/[lat0/]]scale or -JQ[lon0/[lat0/]]width (Cylindrical
Equidistant).
Give the central meridian lon0 (optional), standard par‐
allel lat0 (optional), and scale (1:xxxx or UNIT/degree).
The standard parallel is typically one of these (but can
be any value):
61.7 - Grafarend and Niermann, minimum linear dis‐
tortion
50.5 - Ronald Miller Equirectangular
43.5 - Ronald Miller, minimum continental distor‐
tion
42 - Grafarend and Niermann
37.5 - Ronald Miller, minimum overall distortion
0 - Plate Carree, Simple Cylindrical, Plain/Plane
Chart
-Jtlon0/[lat0/]scale or -JTlon0/[lat0/]width
Give the central meridian lon0, central parallel lat0
(optional), and scale (1:xxxx or UNIT/degree).
-Juzone/scale or -JUzone/width (UTM - Universal Transverse Mer‐
cator [C]).
Give the UTM zone (A,B,1-60[C-X],Y,Z)) and scale (1:xxxx
or UNIT/degree).
Zones: If C-X not given, prepend - or + to enforce south‐
ern or northern hemisphere conventions [northern if south
> 0].
-Jy[lon0/[lat0/]]scale or -JY[lon0/[lat0/]]width (Cylindrical
Equal-Area [E]).
Give the central meridian lon0 (optional), standard par‐
allel lat0 (optional), and scale (1:xxxx or UNIT/degree).
The standard parallel is typically one of these (but can
be any value):
50 - Balthasart
45 - Gall-Peters
37.0666 - Caster
37.4 - Trystan Edwards
37.5 - Hobo-Dyer
30 - Behrman
0 - Lambert (default)
CONIC PROJECTIONS:
-Jblon0/lat0/lat1/lat2/scale or -JBlon0/lat0/lat1/lat2/width
(Albers [E]).
Give projection center lon0/lat0, two standard parallels
lat1/lat2, and scale (1:xxxx or UNIT/degree).
-Jdlon0/lat0/lat1/lat2/scale or -JDlon0/lat0/lat1/lat2/width
(Conic Equidistant)
Give projection center lon0/lat0, two standard parallels
lat1/lat2, and scale (1:xxxx or UNIT/degree).
-Jllon0/lat0/lat1/lat2/scale or -JLlon0/lat0/lat1/lat2/width
(Lambert [C])
Give origin lon0/lat0, two standard parallels lat1/lat2,
and scale along these (1:xxxx or UNIT/degree).
-Jpoly/[lon0/[lat0/]]scale or -JPoly/[lon0/[lat0/]]width ((Amer‐
ican) Polyconic).
Give the central meridian lon0 (optional), reference par‐
allel lat0 (optional, default = equator), and scale along
central meridian (1:xxxx or UNIT/degree).
AZIMUTHAL PROJECTIONS:
Except for polar aspects, -R w/e/s/n will be reset to -Rg. Use
-R<...>r for smaller regions.
-Jalon0/lat0[/horizon]/scale or -JAlon0/lat0[/horizon]/width
(Lambert [E]).
lon0/lat0 specifies the projection center. horizon spec‐
ifies the max distance from projection center (in
degrees, <= 180, default 90). Give scale as 1:xxxx or
radius/lat, where radius is distance in UNIT from origin
to the oblique latitude lat.
-Jelon0/lat0[/horizon]/scale or -JElon0/lat0[/horizon]/width
(Azimuthal Equidistant).
lon0/lat0 specifies the projection center. horizon spec‐
ifies the max distance from projection center (in
degrees, <= 180, default 180). Give scale as 1:xxxx or
radius/lat, where radius is distance in UNIT from origin
to the oblique latitude lat.
-Jflon0/lat0[/horizon]/scale or -JFlon0/lat0[/horizon]/width
(Gnomonic).
lon0/lat0 specifies the projection center. horizon spec‐
ifies the max distance from projection center (in
degrees, < 90, default 60). Give scale as 1:xxxx or
radius/lat, where radius is distance in UNIT from origin
to the oblique latitude lat.
-Jglon0/lat0[/horizon]/scale or -JGlon0/lat0[/horizon]/width
(Orthographic).
lon0/lat0 specifies the projection center. horizon spec‐
ifies the max distance from projection center (in
degrees, <= 90, default 90). Give scale as 1:xxxx or
radius/lat, where radius is distance in UNIT from origin
to the oblique latitude lat.
-Jglon0/lat0/altitude/azimuth/tilt/twist/Width/Height/scale or
-JGlon0/lat0/altitude/azimuth/tilt/twist/Width/Height/width
(General Perspective).
lon0/lat0 specifies the projection center. altitude is
the height (in km) of the viewpoint above local sea
level. If altitude is less than 10, then it is the dis‐
tance from the center of the earth to the viewpoint in
earth radii. If altitude has a suffix r then it is the
radius from the center of the earth in kilometers.
azimuth is measured to the east of north of view. tilt
is the upward tilt of the plane of projection. If tilt is
negative, then the viewpoint is centered on the horizon.
Further, specify the clockwise twist, Width, and Height
of the viewpoint in degrees. Give scale as 1:xxxx or
radius/lat, where radius is distance in UNIT from origin
to the oblique latitude lat.
-Jslon0/lat0[/horizon]/scale or -JSlon0/lat0[/horizon]/width
(General Stereographic [C]).
lon0/lat0 specifies the projection center. horizon spec‐
ifies the max distance from projection center (in
degrees, < 180, default 90). Give scale as 1:xxxx (true
at pole) or lat/1:xxxx (true at standard parallel lat) or
radius/lat (radius in UNIT from origin to the oblique
latitude lat). Note if 1:xxxx is used then to specify
horizon you must also specify the lat as +-90 to avoid
ambiguity.
MISCELLANEOUS PROJECTIONS:
-Jh[lon0/]scale or -JH[lon0/]width (Hammer [E]).
Give the central meridian lon0 (optional) and scale along
equator (1:xxxx or UNIT/degree).
-Ji[lon0/]scale or -JI[lon0/]width (Sinusoidal [E]).
Give the central meridian lon0 (optional) and scale along
equator (1:xxxx or UNIT/degree).
-Jkf[lon0/]scale or -JKf[lon0/]width (Eckert IV) [E]).
Give the central meridian lon0 (optional) and scale along
equator (1:xxxx or UNIT/degree).
-Jk[s][lon0/]scale or -JK[s][lon0/]width (Eckert VI) [E]).
Give the central meridian lon0 (optional) and scale along
equator (1:xxxx or UNIT/degree).
-Jn[lon0/]scale or -JN[lon0/]width (Robinson).
Give the central meridian lon0 (optional) and scale along
equator (1:xxxx or UNIT/degree).
-Jr[lon0/]scale -JR[lon0/]width (Winkel Tripel).
Give the central meridian lon0 (optional) and scale along
equator (1:xxxx or UNIT/degree).
-Jv[lon0/]scale or -JV[lon0/]width (Van der Grinten).
Give the central meridian lon0 (optional) and scale along
equator (1:xxxx or UNIT/degree).
-Jw[lon0/]scale or -JW[lon0/]width (Mollweide [E]).
Give the central meridian lon0 (optional) and scale along
equator (1:xxxx or UNIT/degree).
NON-GEOGRAPHICAL PROJECTIONS:
-Jp[a]scale[/origin][r|z] or -JP[a]width[/origin][r|z] (Polar
coordinates (theta,r))
Optionally insert a after -Jp [ or -JP] for azimuths CW
from North instead of directions CCW from East [Default].
Optionally append /origin in degrees to indicate an angu‐
lar offset [0]). Finally, append r if r is elevations in
degrees (requires s >= 0 and n <= 90) or z if you want to
annotate depth rather than radius [Default]. Give scale
in UNIT/r-unit.
-Jxx-scale[/y-scale] or -JXwidth[/height] (Linear, log, and
power scaling)
Give x-scale (1:xxxx or UNIT/x-unit) and/or y-scale
(1:xxxx or UNIT/y-unit); or specify width and/or height
in UNIT. y-scale=x-scale if not specified separately and
using 1:xxxx implies that x-unit and y-unit are in
meters. Use negative scale(s) to reverse the direction
of an axis (e.g., to have y be positive down). Set height
or width to 0 to have it recomputed based on the implied
scale of the other axis. Optionally, append to x-scale,
y-scale, width or height one of the following:
d Data are geographical coordinates (in degrees).
l Take log10 of values before scaling.
ppower Raise values to power before scaling.
t Input coordinates are time relative to TIME_EPOCH.
T Input coordinates are absolute time.
Default axis lengths (see gmtdefaults) can be invoked
using -JXh (for landscape); -JXv (for portrait) will swap
the x- and y-axis lengths. The default unit for this
installation is either cm or inch, as defined in the file
share/gmt_setup.conf. However, you may change this by
editing your .gmtdefaults4 file(s).
-R xmin, xmax, ymin, and ymax specify the Region of interest. For
geographic regions, these limits correspond to west, east,
south, and north and you may specify them in decimal degrees or
in [+-]dd:mm[:ss.xxx][W|E|S|N] format. Append r if lower left
and upper right map coordinates are given instead of w/e/s/n.
The two shorthands -Rg and -Rd stand for global domain (0/360
and -180/+180 in longitude respectively, with -90/+90 in lati‐
tude). Alternatively, specify the name of an existing grid file
and the -R settings (and grid spacing, if applicable) are copied
from the grid. For calendar time coordinates you may either
give (a) relative time (relative to the selected TIME_EPOCH and
in the selected TIME_UNIT; append t to -JX|x), or (b) absolute
time of the form [date]T[clock] (append T to -JX|x). At least
one of date and clock must be present; the T is always required.
The date string must be of the form [-]yyyy[-mm[-dd]] (Gregorian
calendar) or yyyy[-Www[-d]] (ISO week calendar), while the clock
string must be of the form hh:mm:ss[.xxx]. The use of delim‐
iters and their type and positions must be exactly as indicated
(however, input, output and plot formats are customizable; see
gmtdefaults).
OPTIONS
No space between the option flag and the associated arguments.
-E Sets the viewpoint's azimuth and elevation (for perspective
view) [180/90]. For frames used for animation, you may want to
append + to fix the center of your data domain (or specify a
particular world coordinate point with +wlon0/lat[/z]) which
will project to the center of your page size (or specify the
coordinates of the projected view point with +vx0/y0).
-G Select fill shade, color or pattern for the inside of the
basemap [Default is no fill color]. (See SPECIFYING FILL
below).
-Jz Sets the vertical scaling (for 3-D maps). Same syntax as -Jx.
-K More PostScript code will be appended later [Default terminates
the plot system].
-L 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 [miles if m is
appended; nautical miles if n is appended]. Use -Lf to get a
"fancy" scale [Default is plain]. Append +l to select the
default label which equals the distance unit (km, miles, nauti‐
cal miles) 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
+ffill parameters. (See SPECIFYING PENS and SPECIFYING FILL
below).
-O Selects Overlay plot mode [Default initializes a new plot sys‐
tem].
-P Selects Portrait plotting mode [Default is Landscape, see gmtde‐
faults to change this].
-T 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 sup‐
press 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 ori‐
entations, 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/dla‐
bel, 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 geo‐
graphic and magnetic directions are 10/5/1 and 30/5/1 degrees,
respectively; override these settings by appending
+gints[/mints]. Color and pen attributes are taken from
COLOR_BACKGROUND and TICK_PEN, respectively, while label fonts
and sizes follow the usual annotation, label, and header font
settings.
-U Draw Unix System time stamp on plot. By adding just/dx/dy/, the
user may specify the justification of the stamp and where the
stamp should fall on the page relative to lower left corner of
the plot. For example, BL/0/0 will align the lower left corner
of the time stamp with the lower left corner of the plot.
Optionally, append a label, or c (which will plot the command
string.). The GMT parameters UNIX_TIME, UNIX_TIME_POS, and
UNIX_TIME_FORMAT can affect the appearance; see the gmtdefaults
man page for details. The time string will be in the locale set
by the environment variable TZ (generally local time).
-V Selects verbose mode, which will send progress reports to stderr
[Default runs "silently"].
-X -Y Shift plot origin relative to the current origin by (x-shift,y-
shift) and optionally append the length unit (c, i, m, p). You
can prepend a to shift the origin back to the original position
after plotting, or prepend r [Default] to reset the current
origin to the new location. If -O is used then the default (x-
shift,y-shift) is (0,0), otherwise it is (r1i, r1i) or (r2.5c,
r2.5c). Alternatively, give c to align the center coordinate (x
or y) of the plot with the center of the page based on current
page size.
-Z For 3-D projections: Sets the z-level of the basemap [Default
is at the bottom end of the z-axis].
-c Specifies the number of plot copies. [Default is 1].
SPECIFYING PENS
pen The attributes of lines and symbol outlines as defined by pen is
a comma delimetered list of width, color and texture, each of
which is optional. width can be indicated as a measure (points,
centimeters, inches) or as faint, thin[ner|nest], thick[er|est],
fat[ter|test], or obese. color specifies a gray shade or color
(see SPECIFYING COLOR below). texture is a combination of
dashes `-' and dots `.'.
SPECIFYING FILL
fill The attribute fill specifies the solid shade or solid color (see
SPECIFYING COLOR below) or the pattern used for filling poly‐
gons. Patterns are specified as pdpi/pattern, where pattern
gives the number of the built-in pattern (1-90) or the name of a
Sun 1-, 8-, or 24-bit raster file. The dpi sets the resolution
of the image. For 1-bit rasters: use Pdpi/pattern for inverse
video, or append :Fcolor[B[color]] to specify fore- and back‐
ground colors (use color = - for transparency). See GMT Cook‐
book & Technical Reference Appendix E for information on indi‐
vidual patterns.
SPECIFYING COLOR
color The color of lines, areas and patterns can be specified by a
valid color name; by a gray shade (in the range 0-255); by a
decimal color code (r/g/b, each in range 0-255; h-s-v, ranges
0-360, 0-1, 0-1; or c/m/y/k, each in range 0-1); or by a hexa‐
decimal color code (#rrggbb, as used in HTML). See the gmtcol‐
ors manpage for more information and a full list of color names.
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
psbasemap-R 0/9/0/5 -Jx 1 -Bf 1a2: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
psbasemap-R 1/10000/1e20/1e25 -JX 25cl/15cl -B 2:Wave‐
length:/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 anno‐
tated at 1 my, 4 my, 9 my etc, use
psbasemap-R 0/100/0/5000 -Jx 1p0.5/-0.001 -B 1p:"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
psbasemap-R 0/360/0/1000 -JP 6i -B 30p/100 > polar.ps
CYLINDRICAL MAP PROJECTIONS
Cassini
A 10 -cm-wide basemap using the Cassini projection may be obtained by
psbasemap-R 20/50/20/35 -JC 35/28/10c -P -B 5g5:.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
psbasemap-R 90/180/-50/50 -Jm 0.025i -B 30g30:.Mercator: -Lx
1i/1i/0/5000 > mercator.ps
Miller
A global Miller cylindrical map with scale 1:200,000,000 may be plotted
as
psbasemap-Rg -Jj 180/1:200000000 -B 30g30:.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
psbasemap-R 0/360/-70/70 -Joc 0/0/90/30/0.064cd -B 30g30:."Oblique
Mercator": > oblmerc.ps
Transverse Mercator [conformal]
A regular Transverse Mercator basemap for some region may look like
psbasemap-R 69:30/71:45/-17/-15:15 -Jt 70/1:1000000 -B 15m:."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
psbasemap -R-50/310/-90/90 -JQ 130/25c -B 30g30:."Equidistant Cylindri‐
cal": > 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-R 95/5/108/20r -Ju46/1:10000000 -B 3g3:.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
psbasemap-Rg -JY 180/45/9i -B 30g30:.Gall-Peters: > gall-peters.ps
CONIC MAP PROJECTIONS
Albers [equal-area]
A basemap for middle Europe may be created by
psbasemap-R 0/90/25/55 -Jb 45/20/32/45/0.25c -B 10g10:."Albers Equal-
area": > albers.ps
Lambert [conformal]
Another basemap for middle Europe may be created by
psbasemap-R 0/90/25/55 -Jl 45/20/32/45/0.1i -B 10g10:."Lambert Confor‐
mal Conic": > lambertc.ps
Equidistant
Yet another basemap of width 6 inch for middle Europe may be created by
psbasemap-R 0/90/25/55 -JD 45/20/32/45/6i -B 10g10:."Equidistant
conic": > econic.ps
Polyconic
A basemap for north America may be created by
psbasemap -R-180/-20/0/90 -JPoly/4i -B 30g10/10g10:."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:
psbasemap-Rg -JA-80/-30/15c -B 30g30/15g15:."Lambert Azimuthal": >
lamberta.ps
Follow the instructions for stereographic projection if you want to
impose rectangular boundaries on the azimuthal equal-area map but sub‐
stitute -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:
psbasemap-Rg -JE 125/10/15c -B 30g30/15g15:.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:
psbasemap-Rg -JF-100/40/60/6i -B 30g30/15g15:.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:
psbasemap-Rg -JG 125/10/6i -B 30g30/15g15:.Orthographic: > ortho.ps
General Perspective
The -JG option can be used in a more generalized form, specifying alti‐
tude 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:
psbasemap-Rg -JG-74/41.5/160/210/55/30/30/6i -B 5g1/5g1:."General Per‐
spective": > 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
psbasemap -R-45/45/-90/-60 -Js 0/-90/12c/-60 -B 5g5:."Salinity measure‐
ments": > stereo1.ps
To make a 12 -cm-wide stereographic basemap for Australia from an arbi‐
trary 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-R 100/-45/160/-5fP -JS 130/-30/12c -B 30g30/15g15:."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
psbasemap-Rd -Jh 0/1:200000000 -B 30g30/15g15:.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
psbasemap-Rd -Ji 0/0.02i -B 30g30/15g15:.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:
psbasemap -R-160/-20/-90/90 -Ji-90/0.02i -B 30g30/15g15Wesn -K >
sinus_i.ps
psbasemap -R-20/60/-90/90 -Ji 20/0.02i -B 30g30/15g15wesn -O -K -X 2.8i
>> sinus_i.ps
psbasemap-R 60/200/-90/90 -Ji 130/0.02i -B 30g30/15g15wEsn -O -X 1.6i
>> sinus_i.ps
Eckert IV [equal-area]
Pseudo-cylindrical projection typically used for global maps only. Set
the central longitude and scale, e.g.,
psbasemap-Rg -Jkf 180/0.064c -B 30g30/15g15:."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.,
psbasemap-Rg -Jks 180/0.064c -B 30g30/15g15:."Eckert VI": > eckert6.ps
Robinson
Projection designed to make global maps "look right". Set the central
longitude and width, e.g.,
psbasemap-Rd -JN 0/8i -B 30g30/15g15:.Robinson: > robinson.ps
Winkel Tripel
Yet another projection typically used for global maps only. You can
set the central longitude, e.g.,
psbasemap-R 90/450/-90/90 -JR 270/25c -B 30g30/15g15:."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 -JW 180/25c -B 30g30/15g15:.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 cen‐
tered on the Dateline:
psbasemap-Rg-JV 180/7i -B 30g30/15g15:."Van der Grinten": > grin‐
ten.ps
RESTRICTIONS
For some projections, a spherical earth is implicitly assumed. A warn‐
ing will notify the user if -V is set. Also note that plot titles are
not plotted if -E is given.
BUGS
The -B option is somewhat complicated to explain and comprehend. How‐
ever, it is fairly simple for most applications (see examples).
SEE ALSOgmtcolors(5), gmtdefaults(1), GMT(1)GMT 4.5.14 1 Nov 2015 PSBASEMAP(1)
