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pssegy(1)                             GMT                            pssegy(1)




NAME

       pssegy - Plot a SEGY file on a map


SYNOPSIS

       pssegy SEGYfile  -Jparameters
        -Rregion
        -Ddeviation
        -F[color]   -W [  -Cclip ] [  -Eerror ] [  -I ] [  -K ] [  -Lnsamp ] [
       -Mntrace ] [  -N ] [  -O ] [  -P ] [  -Q<mode><value> ] [  -Sheader ] [
       -Tfilename  ] [  -U[stamp] ] [  -V[level] ] [  -Xx_offset ] [  -Yy_off-
       set ] [ -pflags ] [ -ttransp ]

       Note: No space is allowed between the option flag  and  the  associated
       arguments.


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-spec-
       ified) 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 signifi-
       cant). Standard GMT geometry routines are used so that in principle 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-standard meanings.

       Note  that  the order of operations before the seismic data are plotted
       is deviation*[clip]([bias]+[normalize](sample value)). Deviation deter-
       mines  how  far in the plot coordinates a [normalized][biased][clipped]
       sample value of 1 plots from the trace location.

       The SEGY file should be a disk image of the  tape  format  (i.e.,  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).


REQUIRED ARGUMENTS

       SEGYfile
              Seismic SEGY data set to be imaged.

       -Jparameters (more a|)
              Select map projection.

       -Rwest/east/south/north[/zmin/zmax][+r][+uunit]
              west, east, south, and north specify the region of interest, and
              you   may   specify   them   in   decimal    degrees    or    in
              [A+-]dd:mm[:ss.xxx][W|E|S|N]  format Append +r if lower left and
              upper right map coordinates are given instead  of  w/e/s/n.  The
              two  shorthands  -Rg  and -Rd stand for global domain (0/360 and
              -180/+180 in longitude respectively, with -90/+90 in  latitude).
              Alternatively  for grid creation, give Rcodelon/lat/nx/ny, where
              code is a 2-character combination of L, C, R (for left,  center,
              or  right)  and T, M, B for top, middle, or bottom. e.g., BL for
              lower left.  This indicates which point on a rectangular  region
              the lon/lat coordinate refers to, and the grid dimensions nx and
              ny with grid spacings via -I is used to create the corresponding
              region.   Alternatively,  specify  the  name of an existing grid
              file and the -R settings (and grid spacing, if  applicable)  are
              copied from the grid. Appending +uunit expects projected (Carte-
              sian) coordinates compatible with chosen  -J  and  we  inversely
              project  to determine actual rectangular geographic region.  For
              perspective view (-p), optionally append /zmin/zmax.  In case of
              perspective view (-p), a z-range (zmin, zmax) can be appended to
              indicate the third dimension. This needs to be  done  only  when
              using  the -Jz option, not when using only the -p option. In the
              latter case a perspective view of the plane is plotted, with  no
              third dimension.

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

       -F[color]
              Fill trace (variable area, defaults to filling positive).  Spec-
              ify the color with which the imagemask is filled.

       -W     Draw wiggle trace.

       You must specify at least one of -W and -F.


OPTIONAL ARGUMENTS

       -A     Flip  the  default  byte-swap state (default assumes data have a
              bigendian byte-order).

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

       -Eerror
              Allow  error difference between requested and actual trace loca-
              tions when using -T option.

       -I     Fill negative rather than positive excursions.

       -K (more a|)
              Do not finalize the PostScript plot.

       -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 (more a|)
              Append to existing PostScript plot.

       -P (more a|)
              Select aPortraita plot orientation.

       -Q<mode><value>

              Can be used to change 5 different settings depending on mode:
                     -Qbbias to bias scaled traces (-Qb-0.1 subtracts 0.1 from
                     values).

                     -Qidpi sets the dots-per-inch  resolution  of  the  image
                     [300].

                     -Quredvel  to  apply  reduction  velocity (negative value
                     removes reduction already present).

                     -Qxmult to multiply trace locations by mult.

                     -Qydy to override sample interval in SEGY reel header.

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

       -Tfilename
              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.

       -U[[just]/dx/dy/][c|label] (more a|)
              Draw GMT time stamp logo on plot.

       -V[level] (more a|)
              Select verbosity level [c].

       -X[a|c|f|r][x-shift[u]]

       -Y[a|c|f|r][y-shift[u]] (more a|)
              Shift plot origin.

       -Z     Do not plot traces with zero rms amplitude.

       -p[x|y|z]azim[/elev[/zlevel]][+wlon0/lat0[/z0]][+vx0/y0] (more a|)
              Select perspective view.

       -t[transp] (more a|)
              Set PDF transparency level in percent.

       -^ or just -
              Print  a  short  message  about  the syntax of the command, then
              exits (NOTE: on Windows just use -).

       -+ or just +
              Print an extensive usage (help) message, including the  explana-
              tion  of  any  module-specific  option  (but  not the GMT common
              options), then exits.

       -? or no arguments
              Print a complete usage (help) message, including the explanation
              of all options, then exits.


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

              gmt pssegy wa1.segy -JX5i/-5i -R0/100/0/10 -D1 -C3 -N -So -W -Fblack > 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 variable  area  shaded  red,
       use

              gmt pssegy wa1.segy -JX5i/-5i -R0/100/0/10 -D1 -C3 -Sc -Qx0.1 -Fred -Qb-1 -I > segy.ps


SEE ALSO

       gmt(1), pssegyz(1), segy2grd(1)


COPYRIGHT

       2017, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe



5.4.2                            Jun 24, 2017                        pssegy(1)

gmt5 5.4.2 - Generated Thu Jun 29 15:47:22 CDT 2017
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