NAME

       pssegyz - Create imagemasked postscript from SEGY file


SYNOPSIS

       pssegyz   SEGYfile   -Jparameters  -Rwest/east/south/north  -Ddeviation
       -F[rgb|gray]|-W [ -I] [ -N ] [ -Bbias ] [ -Cclip ] [ -Z ] [ -Xscale ] [
       -Ysample int ] [ -Sheader_x/header_y ] [ -Lnsamp ] [ -Mntrace ] [ -Ure-
       dvel ] [ -Eazimuth/elevation ] [ -O ] [ -K ] [ -P ][ -V  ]


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 .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 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-
              ree))
              -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 manpages.

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

       -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

       -F[rgb|gray]
              Fill trace (variable area, defaults to filling positive). 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 arguments.

       -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, 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.

       -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.

       -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.

       -E     Azimuth and elevation for the 3-D projection.

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

       -bo    Selects binary output. Append s for single precision [Default is
              double].

       -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

       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-
       ality.   I  know that some of the more complex degenerate cases are not
       dealt with correctly or at all; the incidence of such  cases  increases
       as  viewing angles become more oblique, and particularly as the viewing
       elevation increases. Wiggle-trace plotting is not affected.


SEE ALSO

       gmt(GMTMANSECTION), pssegy(GMTMANSECTION)



                                  1 Jan 2004                        PSSEGYZ(l)

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