## NAME

           pssegy - Create imagemasked postscript from SEGY file

## SYNOPSIS

           pssegy SEGYfile -Jparameters -Rwest/east/south/north -Dde
           viation -F[rgb|gray]|-W [ -I] [ -N ] [ -Bbias ] [ -Cclip ]
           [ -Z ] [ -Xscale ] [ -Ysample int ] [ -Sheader ] [ -Lnsamp
           ] [ -Mntrace ] [ -Uredvel ] [ -Tfilename ] [ -Eerror  ]  [
           -O ] [ -K ] [ -P ][ -V  ]

## DESCRIPTION

           pssegy 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 prin
           ciple any map projection may be used, however it is likely
           that  the  geographic  projections will lead to unexpected
           results. Beware also that some parameters  have  non-stan
           dard  meanings.   Note that the order of operations before
           the    seismic    data    are    plotted     is     devia
           tion*[clip]([bias]+[normalize](sample  value)).  Deviation
           determines how far in  the  plot  coordinates  a  [normal
           ized][biased][clipped]  sample  value  of 1 plots from the
           trace location.  The SEGY file should be a disk  image  of
           the  tape  format  (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  MEA
                  SURE_UNIT  setting in .gmtdefaults, but this can be
                  overridden on the command line by appending the  c,
                  i, or m to the scale/width value.

                  CYLINDRICAL PROJECTIONS:

                  -Jclon0/lat0/scale (Cassini)
                  -Jjlon0/scale (Miller)
                  -Jmscale  (Mercator - Greenwich and Equator as ori
                  gin)
                  -Jmlon0/lat0/scale (Mercator -  Give  meridian  and
                  standard parallel)
                  -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 Carree))
                  -Jtlon0/scale   (TM  -  Transverse  Mercator,  with
                  Equator as y = 0)
                  -Jtlon0/lat0/scale (TM - Transverse  Mercator,  set
                  origin)
                  -Juzone/scale (UTM - Universal Transverse Mercator)
                  -Jylon0/lats/scale (Basic Cylindrical Projection)

                  AZIMUTHAL PROJECTIONS:

                  -Jalon0/lat0/scale (Lambert).
                  -Jelon0/lat0/scale (Equidistant).
                  -Jflon0/lat0/horizon/scale (Gnomonic).
                  -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]]  (Linear, log,
                  and power scaling)
                  More details can be found  in  the  psbasemap  man
                  pages.

           -R     west,  east, south, and north specify the Region of
                  interest. To specify boundaries in degrees and min
                  utes  [and  seconds],  use  the  dd:mm[:ss] format.
                  Append r if lower left and upper right map  coordi
                  nates are given instead of wesn.

           -D     gives  the deviation in X units of the plot for 1.0
                  on the scaled trace.

           -F[rgb|gray]
                  Fill trace (variable area, defaults to filling pos
                  itive).  rgb or gray gives the color with which the
                  imagemask is filled.

           -W     Draw wiggle trace.

            Must specify at least one of -W and -F.

## OPTIONS

           No space between the option flag and the associated  argu
           ments.

           -I     Fill negative rather than positive excursions.

           -N     Normalize  trace  by dividing by rms amplitude over
                  full trace length.

           -B     Bias to apply to data (added to sample values).

           -C     Sample value at which to  clip  data  (clipping  is
                  applied to both positive and negative values).

           -Z     Don't plot traces with zero rms amplitude.'

           -X     Multiply  trace locations by scale before plotting.

           -Y     Override sample interval in reel header.

           -S     Read trace locations from trace headers: header  is
                  either c for CDP, o for offset, or b<num> to read a
                  long starting at byte <num> in  the  header  (first
                  byte  corresponds  to  num=0). Default has location
                  given by trace number.

           -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)  grace
                  fully,  but  this parameter limits number of traces
                  that the program attempts to read.

           -U     Apply reduction velocity by shifting traces upwards
                  by   redvel/|offset|.   Negative  velocity  removes
                  existing reduction. Units should be consistent with
                  offset in trace header and sample interval.

           -T     Plot  only  traces  whose location corresponds to a
                  list given in filename.  Order in which traces  are
                  listed  is  not  significant  - the entire space is
                  checked for each trace.

           -E     Allow error difference between requested and actual
                  trace locations when using -T option.

           -K     More   PostScript   code  will  be  appended  later
                  [Default terminates the plot system].

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

           -P     Selects  Portrait  plotting  mode  [GMT  Default is
                  Landscape, see gmtdefaults to change this].

           -V     Selects verbose  mode,  which  will  send  progress
                  reports to stderr [Default runs "silently"].

## 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,
           try

           pssegy wa1.segy -JX5/-5 -R0/100/0/10 -D1 -C3 -N -So -W -F0
           > segy.ps

           To plot the SEGY file wa1.segy with traces plotted at true
           cdp*0.1, clipped at +-3, with bias -1 and  negative  vari
           able area shaded red, try

           pssegy  wa1.segy  -JX5/-5  -R0/100/0/10  -D1 -C3 -Sc -X0.1
           -F255/0/0 -B-1 -I > segy.ps

## SEE ALSO

           gmt(l), pssegyz(l)

                               15 Oct 2001                  PSSEGY(l)