NAME

       pssegyz - Create imagemasked postscript from SEGY file

SYNOPSIS

       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 ]

DESCRIPTION

       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
       not significant).
        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)

       SEGYfile
              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.

              CYLINDRICAL PROJECTIONS:

              -Jclon0/lat0/scale (Cassini)
              -Jjlon0/scale (Miller)
              -Jmscale (Mercator - Greenwich and Equator as origin)
              -Jmlon0/lat0/scale (Mercator - Give meridian and standard paral-
              lel)
              -Joalon0/lat0/azimuth/scale   (Oblique   Mercator  -  point  and
              azimuth)
              -Joblon0/lat0/lon1/lat1/scale (Oblique Mercator - two points)
              -Joclon0/lat0/lonp/latp/scale  (Oblique  Mercator  -  point  and
              pole)
              -Jqlon0/scale  (Equidistant  Cylindrical  Projection (Plate Car-
              -Jglon0/lat0/scale (Orthographic).
              -Jslon0/lat0/[slat/]scale (General Stereographic)

              CONIC PROJECTIONS:

              -Jblon0/lat0/lat1/lat2/scale (Albers)
              -Jdlon0/lat0/lat1/lat2/scale (Equidistant)
              -Jllon0/lat0/lat1/lat2/scale (Lambert)

              MISCELLANEOUS PROJECTIONS:

              -Jhlon0/scale (Hammer)
              -Jilon0/scale (Sinusoidal)
              -Jk[f|s]lon0/scale (Eckert IV (f) and VI (s))
              -Jnlon0/scale (Robinson)
              -Jrlon0/scale (Winkel Tripel)
              -Jvlon0/scale (Van der Grinten)
              -Jwlon0/scale (Mollweide)

              NON-GEOGRAPHICAL PROJECTIONS:

              -Jp[a]scale[/origin] (polar (theta,r)  coordinates,  optional  a
              for azimuths and offset theta [0])
              -Jxx-scale[l|ppow][/y-scale[l|ppow]][d]  (Linear, log, and power
              scaling)
              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.

       -F[rgb|gray]
              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
              length.

       -O     Selects Overlay plot mode [Default initializes a new  plot  sys-
              tem].

       -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-
              ple interval.

       -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.

EXAMPLES

       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

BUGS

       Variable area involves filling four-sided figures of distressing gener-