pssegyz - Create imagemasked postscript from SEGY file
pssegyz SEGYfile -Jparameters -Rwest/east/south/north -Ddeviation
-F[rgb|gray]|-W [ -Bbias ] [ -Cclip ] [ -Eazimuth/elevation ] [ -I ] [
-K ] [ -Lnsamp ] [ -Mntrace ] [ -N ] [ -O ] [ -P ] [
-Sheader_x/header_y ] [ -Uredvel ] [ -V ] [ -Xscale ] [ -Ysample_int ]
[ -Z ]
pssegyz reads a native (IEEE) format SEGY file and produces a
PostScript image of the seismic data. The imagemask operator is used so
that the seismic data are plotted as a 1-bit deep bitmap in a single
(user-specified) color or gray shade, with a transparent background.
The bitmap resolution is taken from the current GMT defaults. The
seismic traces may be plotted at their true locations using information
in the trace headers (in which case order of the traces in the file is
Standard GMT geometry routines are used so that in principle any map
projection may be used, however it is likely that the geographic pro-
jections will lead to unexpected results. Beware also that some parame-
ters have non-standard meanings, and a couple of the options for pssegy
are not available in pssegyz. Note that the order of operations before
the seismic data are plotted is deviation*[clip]([bias]+[normal-
ize](sample value)). Deviation determines how far in the plot coordi-
nates a [normalized][biased][clipped] sample value of 1 plots from the
trace location. The SEGY file should be a disk image of the tape for-
mat (ie 3200 byte text header, which is ignored, 400 byte binary reel
header, and 240 byte header for each trace) with samples as native
real*4 (IEEE real on all the platforms to which I have access)
Seismic data set to be imaged
-J Selects the map projection. Scale is UNIT/degree, 1:xxxxx, or
width in UNIT (upper case modifier). 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/width value. For map height, max dimension, or min
dimension, append h, +, or - to the width, respectively.
-Jmscale (Mercator - Greenwich and Equator as origin)
-Jmlon0/lat0/scale (Mercator - Give meridian and standard paral-
-Joalon0/lat0/azimuth/scale (Oblique Mercator - point and
-Joblon0/lat0/lon1/lat1/scale (Oblique Mercator - two points)
-Joclon0/lat0/lonp/latp/scale (Oblique Mercator - point and
-Jqlon0/scale (Equidistant Cylindrical Projection (Plate Car-
-Jslon0/lat0/[slat/]scale (General Stereographic)
-Jk[f|s]lon0/scale (Eckert IV (f) and VI (s))
-Jrlon0/scale (Winkel Tripel)
-Jvlon0/scale (Van der Grinten)
-Jp[a]scale[/origin] (polar (theta,r) coordinates, optional a
for azimuths and offset theta )
-Jxx-scale[l|ppow][/y-scale[l|ppow]][d] (Linear, log, and power
More details can be found in the psbasemap man pages.
-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 wesn. The
two shorthands -Rg -Rd stand for global domain (0/360 or
-180/+180 in longitude respectively, with -90/+90 in latitude).
For calendar time coordinates you may either give relative time
(relative to the selected TIME_EPOCH and in the selected
TIME_UNIT; append t to -JX|x), or 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 delimiters and their
type and positions must be as indicated (however, input/output
and plotting formats are flexible).
-D gives the deviation in X units of the plot for 1.0 on the scaled
trace, This may be a single number (applied equally in X and Y
directions) or devX/devY
-E Azimuth and elevation for the 3-D projection.
Fill trace (variable area, defaults to filling positive). rgb or
gray gives the color with which the imagemask is filled.
-I Fill negative rather than positive excursions.
-K More PostScript code will be appended later [Default terminates
the plot system].
-L Override number of samples per trace in reel header (program
attempts to determine number of samples from each trace header
if possible to allow for variable length traces).
-M Override number of traces specified in reel header. Program
detects end of file (relatively) gracefully, but this parameter
limits number of traces that the program attempts to read.
-N Normalize trace by dividing by rms amplitude over full trace
-O Selects Overlay plot mode [Default initializes a new plot sys-
-P Selects Portrait plotting mode [GMT Default is Landscape, see
gmtdefaults to change this].
-S Read trace locations from trace headers: header is either c for
CDP, o for offset, b<num> to read a long starting at byte <num>
in the header (first byte corresponds to num=0), or a number to
fix the location.
First parameter for x, second for y. Default has X and Y given
by trace number.
-U Apply reduction velocity by shifting traces upwards by red-
vel/|offset|. Negative velocity removes existing reduction.
Units should be consistent with offset in trace header and sam-
-V Selects verbose mode, which will send progress reports to stderr
[Default runs "silently"].
-X Multiply trace locations by scale before plotting.
-Y Override sample interval in reel header.
-Z Do not plot traces with zero rms amplitude.
To plot the SEGY file wa1.segy with normalized traces plotted at true
offset locations, clipped at +-3 and with wiggle trace and positive
variable area shading in black, use
pssegyz wa1.segy -JX5/-5 -D1 -Jz0.05 -E180/5 -R0/100/0/10/0/10 -C3 -N
-So -W -F0 > segy.ps
Variable area involves filling four-sided figures of distressing gener-
Man(1) output converted with