1PSSEGYZ(1) GMT PSSEGYZ(1)
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6 pssegyz - Create imagemasked postscript from SEGY file
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9 pssegyz SEGYfile -Jparameters
10 -Jz|Zparameters
11 -Rwest/east/south/north[/zmin/zmax][+r]
12 -Ddeviation -F[color] -W [ -Cclip ] [ -I ] [ -K ] [ -Lnsamp ] [
13 -Mntrace ] [ -N ] [ -O ] [ -P ] [ -Q<mode><value> ] [
14 -Sheader_x/header_y ] [ -U[stamp] ] [ -V[level] ] [ -Xx_offset ] [
15 -Yy_offset ] [ -Z ] [ -pflags ] [ -ttransp ]
16 Note: No space is allowed between the option flag and the associated
18 arguments.
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21 pssegyz reads a native (IEEE) format SEGY file and produces a Post‐
22 Script image of the seismic data. The imagemask operator is used so
23 that the seismic data are plotted as a 1-bit deep bitmap in a single
24 (user-specified) color or gray shade, with a transparent background.
25 The bitmap resolution is taken from the current GMT defaults. The seis‐
26 mic traces may be plotted at their true locations using information in
27 the trace headers (in which case order of the traces in the file is not
28 significant). Standard GMT geometry routines are used so that in prin‐
29 ciple any map projection may be used, however it is likely that the
30 geographic projections will lead to unexpected results. Beware that a
31 couple of the options for pssegy are not available in pssegyz.
32 Note that the order of operations before the seismic data are plotted
34 is deviation*[clip]([bias]+[normalize](sample value)). Deviation deter‐
35 mines how far in the plot coordinates a [normalized][biased][clipped]
36 sample value of 1 plots from the trace location.
37 The SEGY file should be a disk image of the tape format (i.e., 3200
39 byte text header, which is ignored, 400 byte binary reel header, and
40 240 byte header for each trace) with samples as native real*4 (IEEE
41 real on all the platforms to which I have access).
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44 SEGYfile
45 Seismic SEGY data set to be imaged.
46 -Jparameters (more ...)
48 Select map projection.
49 -Rwest/east/south/north[/zmin/zmax][+r][+uunit]
51 west, east, south, and north specify the region of interest, and
52 you may specify them in decimal degrees or in
53 [±]dd:mm[:ss.xxx][W|E|S|N] format Append +r if lower left and
54 upper right map coordinates are given instead of w/e/s/n. The
55 two shorthands -Rg and -Rd stand for global domain (0/360 and
56 -180/+180 in longitude respectively, with -90/+90 in latitude).
57 Alternatively for grid creation, give Rcodelon/lat/nx/ny, where
58 code is a 2-character combination of L, C, R (for left, center,
59 or right) and T, M, B for top, middle, or bottom. e.g., BL for
60 lower left. This indicates which point on a rectangular region
61 the lon/lat coordinate refers to, and the grid dimensions nx and
62 ny with grid spacings via -I is used to create the corresponding
63 region. Alternatively, specify the name of an existing grid
64 file and the -R settings (and grid spacing, if applicable) are
65 copied from the grid. Appending +uunit expects projected (Carte‐
66 sian) coordinates compatible with chosen -J and we inversely
67 project to determine actual rectangular geographic region. For
68 perspective view (-p), optionally append /zmin/zmax. In case of
69 perspective view (-p), a z-range (zmin, zmax) can be appended to
70 indicate the third dimension. This needs to be done only when
71 using the -Jz option, not when using only the -p option. In the
72 latter case a perspective view of the plane is plotted, with no
73 third dimension.
74 -Ddeviation
76 gives the deviation in X units of the plot for 1.0 on the scaled
77 trace, This may be a single number (applied equally in X and Y
78 directions) or the pair devX/devY.
79 -F[color]
81 Fill trace (variable area, defaults to filling positive). Spec‐
82 ify the color with which the imagemask is filled.
83 -W Draw wiggle trace.
85 You must specify at least one of -W and -F.
87
89 -A Flip the default byte-swap state (default assumes data have a
90 bigendian byte-order).
91 -Cclip Sample value at which to clip data (clipping is applied to both
93 positive and negative values).
94 -I Fill negative rather than positive excursions.
96 -K (more ...)
98 Do not finalize the PostScript plot.
99 -Lnsamp
101 Override number of samples per trace in reel header (program
102 attempts to determine number of samples from each trace header
103 if possible to allow for variable length traces).
104 -Mntrace
106 Override number of traces specified in reel header. Program
107 detects end of file (relatively) gracefully, but this parameter
108 limits number of traces that the program attempts to read.
109 -N Normalize trace by dividing by rms amplitude over full trace
111 length.
112 -O (more ...)
114 Append to existing PostScript plot.
115 -P (more ...)
117 Select "Portrait" plot orientation.
118 -Q<mode><value>
120 Can be used to change 5 different settings depending on mode:
122 -Qbbias to bias scaled traces (-Qb-0.1 subtracts 0.1 from
123 values).
124 -Qidpi sets the dots-per-inch resolution of the image
126 [300].
127 -Quredvel to apply reduction velocity (-ve removes reduc‐
129 tion already present).
130 -Qxmult to multiply trace locations by mult.
132 -Qydy to override sample interval in reel header.
134 -Sheader_x/header_y
136 Read trace locations from trace headers: headers is either c for
137 CDP, o for offset, b *num* to read a long starting at byte num
138 in the header (first byte corresponds to num=0), or a number to
139 fix the location. First parameter for x, second for y. Default
140 has X and Y given by trace number.
141 -U[[just]/dx/dy/][c|label] (more ...)
143 Draw GMT time stamp logo on plot.
144 -V[level] (more ...)
146 Select verbosity level [c].
147 -X[a|c|f|r][x-shift[u]]
149 -Y[a|c|f|r][y-shift[u]] (more ...)
151 Shift plot origin.
152 -Z Do not plot traces with zero rms amplitude.
154 -p[x|y|z]azim[/elev[/zlevel]][+wlon0/lat0[/z0]][+vx0/y0] (more ...)
156 Select perspective view.
157 -t[transp] (more ...)
159 Set PDF transparency level in percent.
160 -^ or just -
162 Print a short message about the syntax of the command, then
163 exits (NOTE: on Windows just use -).
164 -+ or just +
166 Print an extensive usage (help) message, including the explana‐
167 tion of any module-specific option (but not the GMT common
168 options), then exits.
169 -? or no arguments
171 Print a complete usage (help) message, including the explanation
172 of all options, then exits.
173
175 To plot the SEGY file wa1.segy with normalized traces plotted at true
176 offset locations, clipped at +/-3 and with wiggle trace and positive
177 variable area shading in black, use
178 gmt pssegyz wa1.segy -JX5i/-5i -D1 -Jz0.05i -E180/5 -R0/100/0/10/0/10 \
180 -C3 -N -So -W -Fblack > segy.ps
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183 Variable area involves filling four-sided figures of distressing gener‐
184 ality. I know that some of the more complex degenerate cases are not
185 dealt with correctly or at all; the incidence of such cases increases
186 as viewing angles become more oblique, and particularly as the viewing
187 elevation increases. Wiggle-trace plotting is not affected.
188
190 gmt, pssegy, segy2grd
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193 2019, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
1945.4.5 Feb 24, 2019 PSSEGYZ(1)