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)

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