NAME

     showray - Generate Ray Plots or Plane Wave Beams

SYNOPSIS

     showray [-N input] [-O output]  [-xsrc  xsrc]  [-zsrc  zsrc]
     [-dxray  dxray]  [-vref vref] [-ang ang] [-dang dang] [-tmax
     tmax] [-snap snap] [-dt dt] [-ismoo ismoo] [-h] [-?]

DESCRIPTION

     showray generates ray or plane  wave  beam  plots  at  user-
     selected  time  intervals.  The raytracing algorithm used is
     similar to the one in program kmpw, and therefore will  con-
     tinue  raytracing  beyond  90  degrees (which is not done in
     binmig).  It can be valuable as a tool for selecting  migra-
     tion    and    pre-migration   processing   parameters   for
     raytracing-based migration programs (kmpw,  kmcm,  and  bin-
     mig).   It is useful for visualizing what areas of the velo-
     city model are poorly covered  by  the  raytracing.   Sparse
     raytracing coverage will cause the traveltime maps generated
     in the migrations to be highly interpolated.  An  option  is
     given for generating plane wave beams (pw) or shotpoint (sp)
     rays.

     -N input
          Enter the input velocity dataset name after typing  -N.
          This is a USP-formatted dataset where sample values are
          interval velocities.

     -O output
          Enter the output ray plot dataset name after typing -O.
          This  is  a  USP-formatted file which contains both the
          velocity field and the rays.  It can be displayed using
          XSD.

     -xsrc xsrc
          Enter the flag value after typing -xsrc.
                <= 0 - generate plane wave beams (pw)
                >  0 - generate rays at shotpoint (sp) located
                       at x location (xsrc)
                       trace number of the source relative to the
                       velocity field is determined by nt=xsrc/dx
                       where:
                          nt=trace number for source point
                          xsrc = x location specified by user
                          dx = x increment (Dx1000/1000) of
                               the velocity tape


     -zsrc zsrc
          Enter the depth (ft or meters) of source  after  typing
          -zsrc.

     -dxray dxray
          Enter the delta-x (ft or  meters)  between  rays  after
          typing  -dxray.  This value is for (pw) only and should
          be a multiple of the x increment of the velocity tape.

     -vref vref
          Enter the reference velocity after typing -vref.   This
          value  is for (pw) only. The reference velocity and the
          beam angle (ang) determine the  surface  ray  parameter
          p=sin(ang)/vref.

     -ang ang
          Enter this value after typing -ang.
             for (pw) ang: plane wave rays will be generated at
                           this beam angle
             for (sp) ang: rays will be traced between -ang
                           and +ang at an increment of dang
                           from a surface source at xsrc.

     -dang dang
          Enter the angle increment after typing -dang.   Default
          is 1.  This is for (sp) only.

     -tmax tmax
          Enter the maximum time in ms after typing -tmax.

     -snap snap
          Enter the display time increment  in  ms  after  typing
          -snap.   A  "snapshot" record will be taken of the rays
          at each  multiple  of  the  time  increment  (  nrec  =
          tmax/snap ).

     -dt dt
          Enter the increment (in ms) between ray endpoints after
          typing  -dt.  This  indicates  how  finely  you wish to
          define the line  segments  illustrating  the  rays.   A
          recommended value is 4 ms.

     -ismoo ismoo
          Enter the number of times to  smooth  the  model  after
          typing -ismoo.  A recommended value is 3.

     -h   Enter -h for online help. Program will terminate  after
          printing this.

     -?   Enter this (or '-?' if you are running in  c-shell)  to
          get  online  help.   The  program  will terminate after
          printing this.

BUGS

     None known.

AUTHOR

     N. D. Whitmore, Jr.

COPYRIGHT

     copyright 2001, Amoco Production Company
               All Rights Reserved
          an affiliate of BP America Inc.