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pssegyz(1)                            GMT                           pssegyz(1)


       pssegyz - Create imagemasked postscript from SEGY file


       pssegyz SEGYfile  -Jparameters
        -Ddeviation   -F[color]  -W [  -Cclip ] [  -I ] [  -K ] [  -Lnsamp ] [
       -Mntrace  ]  [   -N  ]  [   -O  ]  [   -P  ]  [   -Q<mode><value>  ]  [
       -Sheader_x/header_y  ]  [  -U[stamp] ] [  -V[level] ] [  -Xx_offset ] [
       -Yy_offset ] [  -Z ] [ -pflags ] [ -ttransp ]

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


       pssegyz  reads  a  native  (IEEE) format SEGY file and produces a Post-
       Script 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 seis-
       mic 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  that  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]+[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).


              Seismic SEGY data set to be imaged.

       -Jparameters (more a|)
              Select map projection.

              west, east, south, and north specify the region of interest, and
              you   may   specify   them   in   decimal    degrees    or    in
              [A+-]dd:mm[][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.

              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 the pair devX/devY.

              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.


       -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).

       -I     Fill negative rather than positive excursions.

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

              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).

              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

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

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


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

                     -Qidpi sets the dots-per-inch  resolution  of  the  image

                     -Quredvel to apply reduction velocity (-ve removes reduc-
                     tion already present).

                     -Qxmult to multiply trace locations by mult.

                     -Qydy to override sample interval in reel header.

              Read trace locations from trace headers: headers 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.

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

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


       -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.


       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 pssegyz wa1.segy -JX5i/-5i -D1 -Jz0.05i -E180/5 -R0/100/0/10/0/10 \
                      -C3 -N -So -W -Fblack >


       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.


       gmt(1), pssegy(1), segy2grd(1)


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

5.4.2                            Jun 24, 2017                       pssegyz(1)

gmt5 5.4.2 - Generated Thu Jun 29 15:48:05 CDT 2017
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