Plot raster or EPS images
gmt psimage imagefile [ -B[p|s]parameters ] [ -Drefpoint ] [ -Fbox ] [ -G[color][+b|f|t] ] [ -I ] [ -Jparameters ] [ -K ] [ -M ] [ -O ] [ -P ] [ -Rwest/east/south/north[/zmin/zmax][+r][+uunit] ] [ -U[stamp] ] [ -V[level] ] [ -X[a|c|f|r][xshift] ] [ -Y[a|c|f|r][yshift] ] [ -pflags ] [ -ttransp ] [ --PAR=value ]
image reads an Encapsulated PostScript file or a raster image file and plots it on a map. The image can be scaled arbitrarily, and 1-bit raster images can be (1) inverted, i.e., black pixels (on) becomes white (off) and vice versa, or (2) colorized, by assigning different foreground and background colors, and (3) made transparent where one of back- or foreground is painted only. As an option, the user may choose to convert colored raster images to grayscale using TV’s YIQ-transformation. For raster files, the user can select which color to be made transparent. The user may also choose to replicate the image which, when preceded by appropriate clip paths, may allow larger custom-designed fill patterns to be implemented (the -Gp mechanism offered in most GMT programs is limited to rasters smaller than 146 by 146).
This must be an Encapsulated PostScript (EPS) file or a raster image. An EPS file must contain an appropriate BoundingBox. A raster file can have a depth of 1, 8, 24, or 32 bits and is read via GDAL.
- -D[g|j|J|n|x]refpoint+rdpi+w[-]width[/height][+jjustify][+nnx[/ny] ][+odx[/dy]]
Sets reference point on the map for the image using one of four coordinate systems:
Append xx/y for plot coordinates (append cm, inch, or ppoint).
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 text). 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. Specify image size in one of two ways: Use +rdpi to set the dpi of the image in dots per inch, or use +w[-]width[/height] to set the width (and height) of the image in plot coordinates (inches, cm, etc.). If height is not given, the original aspect ratio of the image is maintained. If width is negative we use the absolute value and interpolate image to the device resolution using the PostScript image operator. If neither size nor dpi is set then we revert to the default dpi [GMT_GRAPHICS_DPU]. Optionally, use +nnx[/ny] to replicate the image nx times horizontally and ny times vertically. If ny is omitted, it will be identical to nx [Default is 1/1].
Without further options, draws a rectangular border around the image using MAP_FRAME_PEN. The following modifiers can be appended to -F, with additional explanation and examples provided in the The background panel cookbook section:
+cclearance where clearance is either gap, xgap/ygap, or lgap/rgap/bgap/tgap and gap gives a uniform clearance, xgap/ygap gives separate clearances in the x- and y- directions, and lgap/rgap/bgap/tgap gives individual clearances between the map embellishment and the border for each side.
+gfill to fill the box with a color specified by fill [default is no fill].
+i[[gap/]pen] to draw a secondary, inner border as well. Optionally, specify the gap between the inner and outer border and the pen for the inner border [default is a uniform gap between borders of 2p and the MAP_DEFAULT_PEN].
+ppen to specify different pen attributes.
+r[radius] to draw rounded rectangular borders instead with a corner radius set by radius (append units) [defaults is 6p].
+s[[dx/dy/][shade]] to draw an offset background shaded region. Here, dx/dy indicates the shift relative to the foreground frame [default is 4p/-4p] and shade sets the fill style to use for shading [default is gray50].
Change certain pixel values to another color or make them transparent. For 1-bit images you can specify an alternate color for the background (+b) or the foreground (+f) pixels, or give no color to make those pixels transparent. Alternatively, for color images you can select a single color that should be made transparent instead (+t).
Invert 1-bit image before plotting. This is what is done when you use -GP to invert patterns in other GMT plotting programs. Ignored if used with color images.
Specify the projection. (Used only with -p)
Convert color image to monochrome grayshades using the (television) YIQ-transformation.
For perspective view -p, optionally append /zmin/zmax. (more …)
- -p[x|y|z]azim[/elev[/zlevel]][+wlon0/lat0[/z0]][+vx0/y0] (more …)
- -ttransp[/transp2] (more …)
Set transparency level(s) in percent.
- -^ or just -
Print a short message about the syntax of the command, then exit (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 exit.
- -? or no arguments
Print a complete usage (help) message, including the explanation of all options, then exit.
Temporarily override a GMT default setting; repeatable. See gmt.conf for parameters.
Classic Mode Arguments¶
These options are used to manipulate the building of layered GMT PostScript plots in classic mode. They are not available when using GMT modern mode.
- -K (more …)
Do not finalize the PostScript plot.
- -O (more …)
Append to existing PostScript plot.
- -P (more …)
Select “Portrait” plot orientation.
To plot the remote image needle.jpg, scaling it be 7 cm wide (height is scaled accordingly), use:
gmt psimage @needle.jpg -Dx0/0+w7c > image.ps
To plot the same file but reversing the bands, use:
gmt psimage @needle.jpg+b2,1,0 -Dx0/0+w7c > image.ps
To only plot its red band as gray shade, use:
gmt psimage @needle.jpg+b0 -Dx0/0+w7c > image.ps
To include an Encapsulated PostScript file gallo.eps with its upper right corner 2 inch to the right and 1 inch up from the current location, and have its width scaled to 3 inches, while keeping the aspect ratio, use:
gmt psimage @gallo.eps -Dx2i/1i+jTR+w3i > image.ps
To replicate the 1-bit remote raster image vader1.png, colorize it (dark gray background and yellow foreground), and setting each of 6 by 12 tiles to be 2.5 cm wide, use:
gmt psimage @vader1.png -Gdarkgray+b -Gyellow+f -Dx0/0+w2.5c+n6/12 -P > image.ps