Provided by: gmt-common_5.4.3+dfsg-1_all 
NAME
psscale - Plot a gray or color scale-bar on maps
SYNOPSIS
psscale -Drefpoint [ -B[p|s]parameters ] [ -Ccpt ] [ -Fbox ] [ -Gzlo/zhi ] [
-I[max_intens|low_i/high_i] ] [ -Jparameters ] [ -Jz|Zparameters ] [ -K ] [ -L[i][gap] ] [ -M ] [
-N[p|dpi ]] [ -O ] [ -P ] [ -Q ] [ -Rregion ] [ -S ] [ -U[stamp] ] [ -V[level] ] [ -Wscale ] [
-Xx_offset ] [ -Yy_offset ] [ -Zzfile ] [ -pflags ] [ -ttransp ]
Note: No space is allowed between the option flag and the associated arguments.
DESCRIPTION
psscale plots gray scales or color scales on maps. Both horizontal and vertical scales are supported. For
CPTs with gradational colors (i.e., the lower and upper boundary of an interval have different colors)
psscale will interpolate to give a continuous scale. Variations in intensity due to shading/illumination
may be displayed by setting the option -I. Colors may be spaced according to a linear scale, all be equal
size, or by providing a file with individual tile widths. The font used for the annotations along the
scale and optional units is specified by FONT_ANNOT_PRIMARY. If a label is requested, it is plotted with
FONT_LABEL.
REQUIRED ARGUMENTS
-D[g|j|J|n|x]refpoint[+wlength[/width]][+e[b|f][length]][+h|v][+jjustify][+m[a|c|l|u]][+n[txt]][+odx[/dy]]
Defines the reference point on the map for the color scale using one of four coordinate systems:
(1) Use -Dg for map (user) coordinates, (2) use -Dj or -DJ for setting refpoint via a 2-char
justification code that refers to the (invisible) map domain rectangle, (3) use -Dn for normalized
(0-1) coordinates, or (4) use -Dx for plot coordinates (inches, cm, etc.). All but -Dx requires
both -R and -J to be specified. For -Dj or -DJ with codes TC, BC, ML, MR (i.e., centered on one
of the map sides) we pre-calculate all further settings. Specifically, the length is set to 80%
of the map side, horizontal or vertical depends on the side, the offset is MAP_LABEL_OFFSET for Dj
with an extra offset MAP_FRAME_WIDTH for DJ, and annotations are placed on the side of the scale
facing away from the map frame. However, you can override any of these with these modifiers:
Append +w followed by the length and width of the color bar. If width is not specified then it is
set to 4% of the given length. Give a negative length to reverse the scale bar. Append +h to get
a horizontal scale [Default is vertical (+v)]. By default, the anchor point on the scale is
assumed to be the bottom left corner (BL), but this can be changed by appending +j followed by a
2-char justification code justify (see pstext). Note: If -Dj is used then justify defaults to the
same as refpoint, if -DJ is used then justify defaults to the mirror opposite of refpoint.
Finally, add +o to offset the color scale by dx/dy away from the refpoint point in the direction
implied by justify (or the direction implied by -Dj or -DJ). Add sidebar triangles for back-
and/or foreground colors with +e. Append f (foreground) or b (background) for only one sidebar
triangle [Default gives both]. Optionally, append triangle height [Default is half the barwidth].
Move text to opposite side with +m[a|c|l|u]. Horizontal scale bars: Move annotations and labels
above the scale bar [Default is below]; the unit remains on the left. Vertical scale bars: Move
annotations and labels to the left of the scale bar [Default is to the right]; the unit remains
below. Append one or more of a, l or u to control which of the annotations, label, and unit that
will be moved to the opposite side. Append c if you want to print a vertical label as a column of
characters (does not work with special characters). Append +n to plot a rectangle with the NaN
color at the start of the bar, append text to change label from NaN.
OPTIONAL ARGUMENTS
-B[p|s]parameters
Set annotation, tick, and gridline interval for the colorbar. The x-axis label will plot beneath a
horizontal bar (or vertically to the right of a vertical bar), except when using -A. As an option,
use the y-axis label to plot the data unit to the right of a horizontal bar (and above a vertical
bar). When using -Ba or -Baf annotation and/or minor tick intervals are chosen automatically. If
-B is omitted, or no annotation intervals are provided, the default is to annotate every color
level based on the numerical entries in the CPT (which may be overridden by ULB flags in the CPT).
To specify custom text annotations for intervals, you must append ;annotation to each z-slice in
the CPT.
-Ccpt cpt is the CPT to be used. By default all color changes are annotated. To use a subset, add an
extra column to the CPT with a L, U, or B to annotate Lower, Upper, or Both color segment
boundaries (but see -B). If not given, psscale will read stdin. Like grdview, psscale can
understand pattern specifications in the CPT. For CPTs where the z range is in meters, it may be
useful to change to another unit when plotting. To do so, append +Uunit to the file name.
Likewise, if the CPT uses another unit than meter and you wish to plot the CPT versus meters,
append +uunit. If a GMT master dynamic CPT is given instead then its z-range will be set to its
default range (if it has one) before plotting.
-F[+cclearances][+gfill][+i[[gap/]pen]][+p[pen]][+r[radius]][+s[[dx/dy/][shade]]]
Without further options, draws a rectangular border around the scale using MAP_FRAME_PEN; specify
a different pen with +ppen. Add +gfill to fill the scale box [no fill]. Append +cclearance where
clearance is either gap, xgap/ygap, or lgap/rgap/bgap/tgap where these items are uniform, separate
in x- and y-direction, or individual side spacings between scale and border. Append +i to draw a
secondary, inner border as well. We use a uniform gap between borders of 2p and the
MAP_DEFAULTS_PEN unless other values are specified. Append +r to draw rounded rectangular borders
instead, with a 6p corner radius. You can override this radius by appending another value.
Finally, append +s to draw an offset background shaded region. Here, dx/dy indicates the shift
relative to the foreground frame [4p/-4p] and shade sets the fill style to use for shading
[gray50].
-Gzlo/zhi
Truncate the incoming CPT so that the lowest and highest z-levels are to zlo and zhi. If one of
these equal NaN then we leave that end of the CPT alone. The truncation takes place before the
plotting.
-I[max_intens|low_i/high_i]
Add illumination effects. Optionally, set the range of intensities from - to + max_intens. If not
specified, 1 is used. Alternatively, append low/high intensities to specify an asymmetric range
[Default is no illumination].
-Jparameters (more …)
Select map projection.
-Jz|Zparameters (more …)
Set z-axis scaling; same syntax as -Jx.
-K (more …)
Do not finalize the PostScript plot.
-L[i][gap]
Gives equal-sized color rectangles. Default scales rectangles according to the z-range in the CPT
(Also see -Z). If set, any equal interval annotation set with -B will be ignored. If gap is
appended and the CPT is discrete we will center each annotation on each rectangle, using the lower
boundary z-value for the annotation. If i is prepended we annotate the interval range instead. If
-I is used then each rectangle will have its constant color modified by the specified intensity.
-M Force a monochrome graybar using the (television) YIQ transformation.
-N[p|dpi]
Controls how the color scale is represented by the PostScript language. To preferentially draw
color rectangles (e.g., for discrete colors), append p. Otherwise we will preferentially draw
images (e.g., for continuous colors). Optionally append effective dots-per-inch for rasterization
of color scales [600].
-O (more …)
Append to existing PostScript plot.
-P (more …)
Select “Portrait” plot orientation.
-Q Select logarithmic scale and power of ten annotations. All z-values in the CPT will be converted
to p = log10(z) and only integer p values will be annotated using the 10^p format [Default is
linear scale].
-Rwest/east/south/north[/zmin/zmax][+r][+uunit]
west, east, south, and north specify the region of interest, 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 latitude). Alternatively for grid
creation, give Rcodelon/lat/nx/ny, where code is a 2-character combination of L, C, R (for left,
center, or right) and T, M, B for top, middle, or bottom. e.g., BL for lower left. This indicates
which point on a rectangular region the lon/lat coordinate refers to, and the grid dimensions nx
and ny with grid spacings via -I is used to create the corresponding region. Alternatively,
specify the name of an existing grid file and the -R settings (and grid spacing, if applicable)
are copied from the grid. Appending +uunit expects projected (Cartesian) coordinates compatible
with chosen -J and we inversely project to determine actual rectangular geographic region. For
perspective view (-p), optionally append /zmin/zmax. In case of perspective view (-p), a z-range
(zmin, zmax) can be appended to indicate the third dimension. This needs to be done only when
using the -Jz option, not when using only the -p option. In the latter case a perspective view of
the plane is plotted, with no third dimension.
For perspective view p, optionally append /zmin/zmax. (more …)
-S Do not separate different color intervals with black grid lines.
-U[[just]/dx/dy/][c|label] (more …)
Draw GMT time stamp logo on plot.
-V[level] (more …)
Select verbosity level [c].
-Wscale
Multiply all z-values in the CPT by the provided scale. By default the CPT is used as is.
-X[a|c|f|r][x-shift[u]]
-Y[a|c|f|r][y-shift[u]] (more …)
Shift plot origin.
-Zzfile
File with colorbar-width per color entry. By default, width of entry is scaled to color range,
i.e., z = 0-100 gives twice the width as z = 100-150 (Also see -L).
-p[x|y|z]azim[/elev[/zlevel]][+wlon0/lat0[/z0]][+vx0/y0] (more …)
Select perspective view. (Required -R and -J for proper functioning).
-t[transp] (more …)
Set PDF transparency level in percent.
-^ or just -
Print a short message about the syntax of the command, then exits (NOTE: on Windows just use -).
-+ or just +
Print an extensive usage (help) message, including the explanation of any module-specific option
(but not the GMT common options), then exits.
-? or no arguments
Print a complete usage (help) message, including the explanation of all options, then exits.
EXAMPLES
To plot a a horizontal color scale (12 cm long; 0.5 cm wide) at the reference point (8,1) (paper
coordinates) with justification at top center and automatic annotation interval, do
gmt makecpt -T-200/1000/100 -Crainbow > t.cpt
gmt psscale -Ct.cpt -Dx8c/1c+w12c/0.5c+jTC+h -Bxaf+l"topography" -By+lkm > map.ps
To append a vertical color scale (7.5 cm long; 1.25 cm wide) to the right of a plot that is 6 inch wide
and 4 inch high, using illumination, and show back- and foreground colors, and annotating every 5 units,
we provide the reference point and select the left-mid anchor point via
gmt psscale -Dx6.5i+jLM/2i+w7.5c/1.25c+e -O -Ccolors.cpt -I -Bx5+lBATHYMETRY -By+lm >> map.ps
To overlay a horizontal color scale (4 inches long and default width) above a Mercator map produced by a
previous call, ensuring a 2 cm offset from the map frame, use
gmt psscale -DjCT+w4i+o0/2c+h -O -Ccolors.cpt -Baf -R -J >> map.ps
NOTES
When the CPT is discrete and no illumination is specified, the color bar will be painted using polygons.
For all other cases we must paint with an image. Some color printers may give slightly different colors
for the two methods given identical RGB values.
SEE ALSO
gmt, makecpt gmtlogo, grd2cpt psimage, pslegend
COPYRIGHT
2018, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
5.4.3 Jan 03, 2018 PSSCALE(1gmt)