PS2RASTER(1) Generic Mapping Tools PS2RASTER(1)NAMEps2raster - Converts one or several PostScript file(s) to other formats
using GhostScript
SYNOPSISps2rasterpsfile(s) [ -A[u|-] ] [ -Cgs_option ] [ -Doutdir ] [ -Ereso‐
lution ] [ -Gghost_path ] [ -Llistfile ] [ -P ] [ -Q[g|t][1|2|4] ] [ -S
] [ -Tb|e|f|j|g|G|m|t ] [ -V ] [ -W[+g][+tdocname][+nlayername][+aalt‐
mode[alt]][+lminLOD/maxLOD][+fminfade/maxfade][+uURL] ]
DESCRIPTIONps2raster converts one or more PostScript files to other formats (BMP,
EPS, JPEG, PDF, PNG, PPM, TIFF) using GhostScript. Input file names are
read from the command line or from a file that lists them. The size of
the resulting images is determined by the BoundingBox (or HiResBound‐
ingBox, if present). As an option, a tight (HiRes)BoundingBox may be
computed first. As another option, it can compute ESRI type world files
used to reference, for instance, tif files and make them be recognized
as geotiff.
psfiles
Names of PostScript files to be converted. The output files will
have the same name (unless -F is used) but with the conventional
extension name associated to the raster format (e.g., .jpg for
the jpeg format). Use -D to redirect the output to a different
directory.
OPTIONS-A Adjust the BoundingBox and HiResBoundingBox to the minimum
required by the image content. Append u to first remove any
GMT-produced time-stamps. Use -A- to override any automatic
setting of -A by -W.
-C Specify a single, custom option that will be passed on to Ghost‐
Script as is. Repeat to add several options [none].
-D Sets an alternative output directory (which must exist) [Default
is the same directory as the PS files]. Use -D. to place the
output in the current directory instead.
-E Set raster resolution in dpi [default = 720 for PDF, 300 for
others].
-F Force the output file name. By default output names are con‐
structed using the input names as base, which are appended with
an appropriate extension. Use this option to provide a different
name, but without extension. Extension is still determined auto‐
matically.
-G Full path to your GhostScript executable. NOTE: For Unix sys‐
tems this is generally not necessary. Under Windows, ghost‐
script path is now fetch from the registry. If this fails you
can still add the GS path to system's path or give the full path
here. (e.g., -G c:\programs\gs\gs9.02\bin\gswin32c). WARNING:
because of the poor decision of embedding the bits on the gs exe
name we cannot satisfy both the 32 and 64 bits ghostscript exe‐
cutable names. So in case of 'get from registry' failure the
default name (when no -G is used) is the one of the 64 bits ver‐
sion, or gswin32c
-L The listfile is an ASCII file with the names of the PostScript
files to be converted.
-N This option is obsolete. Use -S to print the GhostScript com‐
mand, if applicable. Use -Te to save the intermediate EPS file.
-P Force Portrait mode. All Landscape mode plots will be rotated
back so that they show unrotated in Portrait mode. This is prac‐
tical when converting to image formats or preparing EPS or PDF
plots for inclusion in documents.
-Q Set the anti-aliasing options for graphics or text. Append the
size of the subsample box (1, 2, or 4) [4]. Default is no anti-
aliasing (same as bits = 1).
-S Print to standard output the GhostScript command after it has
been executed.
-T Sets the output format, where b means BMP, e means EPS, f means
PDF, j means JPEG, g means PNG, G means transparent PNG
(untouched regions are transparent), m means PPM, and t means
TIFF [default is JPEG]. For bjgt you can append - to get a
grayscale image only. The EPS format can be combined with any
of the other formats. For example, -Tef creates both an EPS and
a PDF file.
-V Selects verbose mode, which will send progress reports to stderr
[Default runs "silently"].
-W Write a ESRI type world file suitable to make (e.g) .tif files
be recognized as geotiff by softwares that know how to do it. Be
aware, however, that different results are obtained depending on
the image contents and if the -B option has been used or not.
The trouble with the -B option is that it creates a frame and
very likely its annotations. That introduces pixels outside the
map data extent, and therefore the map extents estimation will
be wrong. To avoid this problem use --BASEMAP_TYPE=inside
option which plots all annotations and ticks inside the image
and therefore does not compromise the coordinate computations.
Pay attention also to the cases when the plot has any of the
sides with whites only because than the algorithm will fail mis‐
erably as those whites will be eaten by the GhostScript. In that
case you really must use -B or use a slightly off-white color.
Together with -V it prints on screen the gdal_translate
(gdal_translate is a command line tool from the GDAL package)
command that reads the raster + world file and creates a true
geotiff file. Use -W+g to do a system call to gdal_translate and
create a geoTIFF image right away. The output file will have a
.tiff extension.
The world file naming follows the convention of jamming a 'w' in
the file extension. So, if output is tif -Tt the world file is a
.tfw, for jpeg we have a .jgw and so on. This option automati‐
cally sets -A -P.
Use -W+k to create a minimalist KML file that allows loading the
image in GoogleEarth. Note that for this option the image must
be in geographical coordinates. If not, a warning is issued but
the KML file is created anyway. Several modifier options are
available to customize the KML file in the form of +opt strings.
Append +ttitle to set the document title [GMT KML Document],
+nlayername to set the layer name, and +a/altmode[altitude] to
select one of 5 altitude modes recognized by Google Earth that
determines the altitude (in m) of the image: G clamped to the
ground, g append altitude relative to ground, a append absolute
altitude, s append altitude relative to seafloor, and S clamp it
to the seafloor. Control visibility of the layer with the
+lminLOD/maxLOD and +fminfade/maxfade options. FInally, if you
plan to leave the image itself on a server and only distribute
the KML, use +uURL to prepend the URL to the image reference.
See the KML documentation for further explanation
(http://code.google.com/apis/kml/documentation/).
Further notes on the creation of georeferenced rasters.
ps2raster can create a georeferenced raster image with a world
file OR uses GDAL to convert the GMT PostScript file to geotiff.
GDAL uses Proj.4 for it's projection library. To provide with
the information it needs to do the georeferencing, GMT 4.5
embeds a comment near the start of the PostScript file defining
the projection using Proj.4 syntax. Users with pre-GMT v4.5
PostScript files, or even non-GMT ps files, can provide the
information ps2raster requires by manually editing a line into
the PostScript file, prefixed with %%PROJ.
For example the command pscoast -JM0/12c -R-10/-4/37/43 -W1 -Di
-Bg30m --BASEMAP_TYPE=inside > cara.ps
adds this comment line
%%PROJ: merc -10.0-4.0 37.0 43.0 -1113194.908-445277.963
4413389.889 5282821.824 +proj=merc +lon_0=0 +k=-1 +x_0=0 +y_0=0
+a=6378137.0 +b=6356752.314245
where 'merc' is the keyword for the coordinate conversion; the 2
to 5th elements contain the map limits, 6 to 9th the map limits
in projected coordinates and the rest of the line has the regu‐
lar proj4 string for this projection.
NOTES
The conversion to raster images (BMP, JPEG, PNG, PPM or TIFF) inher‐
ently results in loss of details that are available in the original
PostScript file. Choose a resolution that is large enough for the
application that the image will be used for. For web pages, smaller dpi
values suffice, for Word documents and PowerPoint presentations a
higher dpi value is recommended. ps2raster uses the loss-less Flate
compression technique when creating JPEG, PNG and TIFF images.
EPS is a vector, not a raster format. Therefore, the -E option has no
effect on the creation of EPS files. Using the option -Te will remove
PageSize commands from the PostScript file and will adjust the Bound‐
ingBox when the -A option is used. Note the original and required
BoundingBox is limited to integer points, hence Adobe added the
optional HiResBoundingBox to add more precision in sizing. The -A
option calculates both and writes both to the EPS file used in the ras‐
terization (and output if -Te is set).
Although PDF is also a vector format, the -E option has an effect on
the resolution of pattern fills and fonts that are stored as bitmaps in
the document. ps2raster therefore uses a larger default resolution when
creating PDF files. -E also determines the resolution of the bounding‐
box values used to indicate the size of the output PDF. In order to
obtain high-quality PDF files, the /prepress options are in effect,
allowing only loss-less Flate compression of raster images embedded in
the PostScript file.
Although ps2raster was developed as part of the GMT, it can be used to
convert PostScript files created by nearly any graphics program. How‐
ever, -Au is GMT-specific.
See Appendix C of the GMT Technical Reference and Cookbook for more
information on how ps2raster is used to produce graphics that can be
inserted into other documents (articles, presentations, posters, etc.).
EXAMPLES
To convert the file psfile.ps to PNG using a tight BoundingBox and
rotating it back to normal orientation in case it was in Landscape
mode:
ps2raster psfile.ps -A -P -Tg
To create a simple linear map with pscoast and convert it to tif with a
.tfw the tight BoundingBox computation.
pscoast -JX12cd -R-10/-4/37/43 -W1-Di-Bg30m-P-G200
--BASEMAP_TYPE=inside > cara.ps
ps2raster cara -Tt -W
To create a Mercator version of the above example and use GDAL to pro‐
duce a true geotiff file.
pscoast -JM0/12c -R-10/-4/37/43 -W1-Di-Bg30m-P-G200
--BASEMAP_TYPE=inside > cara.ps
gdalwarp -s_srs +proj=merc cara.tif carageo.tiff
To create a Polar Stereographic geotiff file of Patagonia
pscoast -JS-55/-60/15c -R-77/-55/-57.5/-48r -Di-Gred-P-Bg2
--BASEMAP_TYPE=inside > patagonia.ps
ps2raster patagonia.ps -Tt -W+g -V
To create a simple KMZ file for use in Google Earth, try
grdimage lonlatgrid.nc -Jx1 -Ccolors.cpt -P -B0g2 --BASEMAP_TYPE=inside
> tile.ps
ps2raster tile.ps -Tg -W+k+t"my title"+l256/-1 -V
(These commands assume that GhostScript can be found in your system's
path.)
BINARY DATA
GMT programs can produce binary PostScript image data and this is
determined by the default setting PS_IMAGE_FORMAT. Because ps2raster
needs to process the input files on a line-by-line basis you need to
make sure the image format is set to ascii and not bin.
GHOSTSCRIPT OPTIONS
Most of the conversions done in ps2raster are handled by GhostScript.
On most Unixes this program is available as gs; for Windows there is a
version called gswin32c. GhostScript accepts a rich selection of com‐
mand-line options that modify its behavior. Many of these are set
indirectly by the options available above. However, hard-core usage
may require some users to add additional options to fine-tune the
result. Use -S to examine the actual command used, and add custom
options via one or more instances of the -C option. For instance, to
turn on image interpolation for all images, improving image quality for
scaled images at the expense of speed, use -C-dDOINTERPOLATE. See
www.ghostscript.com for complete documentation.
SEE ALSOGMT(1), gs(1)GMT 4.5.14 1 Nov 2015 PS2RASTER(1)
