PSSEGYZ(1) Generic Mapping Tools PSSEGYZ(1)NAMEpssegyz - Create imagemasked postscript from SEGY file
SYNOPSISpssegyz SEGYfile -Jparameters -Jz|Zparameters
-Rwest/east/south/north[/zmin/zmax][r] -Ddeviation -F[rgb|gray]|-W [
-Bbias ] [ -Cclip ] [ -Eazim/elev[+wlon/lat[/z]][+vx0/y0] ] [ -I ] [ -K
] [ -Lnsamp ] [ -Mntrace ] [ -N ] [ -O ] [ -P ] [ -Sheader_x/header_y ]
[ -Uredvel ] [ -V ] [ -Xscale ] [ -Ysample_int ] [ -Z ]
DESCRIPTIONpssegyz 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
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 projections will lead to unexpected results. Beware also
that some parameters 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 devia‐
tion*[clip]([bias]+[normalize](sample value)). Deviation determines 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 (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 .gmtdefaults4, but this
can be overridden on the command line by appending c, i, or m to
the scale/width value. When central meridian is optional,
default is center of longitude range on -R option. Default
standard parallel is the equator. For map height, max dimen‐
sion, or min dimension, append h, +, or - to the width, respec‐
tively.
More details can be found in the psbasemap man pages.
CYLINDRICAL PROJECTIONS:
-Jclon0/lat0/scale (Cassini)
-Jcyl_stere/[lon0/[lat0/]]scale (Cylindrical Stereographic)
-Jj[lon0/]scale (Miller)
-Jm[lon0/[lat0/]]scale (Mercator)
-Jmlon0/lat0/scale (Mercator - Give meridian and standard paral‐
lel)
-Jo[a]lon0/lat0/azimuth/scale (Oblique Mercator - point and
azimuth)
-Jo[b]lon0/lat0/lon1/lat1/scale (Oblique Mercator - two points)
-Joclon0/lat0/lonp/latp/scale (Oblique Mercator - point and
pole)
-Jq[lon0/[lat0/]]scale (Cylindrical Equidistant)
-Jtlon0/[lat0/]scale (TM - Transverse Mercator)
-Juzone/scale (UTM - Universal Transverse Mercator)
-Jy[lon0/[lat0/]]scale (Cylindrical Equal-Area)
CONIC PROJECTIONS:
-Jblon0/lat0/lat1/lat2/scale (Albers)
-Jdlon0/lat0/lat1/lat2/scale (Conic Equidistant)
-Jllon0/lat0/lat1/lat2/scale (Lambert Conic Conformal)
-Jpoly/[lon0/[lat0/]]scale ((American) Polyconic)
AZIMUTHAL PROJECTIONS:
-Jalon0/lat0[/horizon]/scale (Lambert Azimuthal Equal-Area)
-Jelon0/lat0[/horizon]/scale (Azimuthal Equidistant)
-Jflon0/lat0[/horizon]/scale (Gnomonic)
-Jglon0/lat0[/horizon]/scale (Orthographic)
-Jglon0/lat0/altitude/azimuth/tilt/twist/Width/Height/scale
(General Perspective).
-Jslon0/lat0[/horizon]/scale (General Stereographic)
MISCELLANEOUS PROJECTIONS:
-Jh[lon0/]scale (Hammer)
-Ji[lon0/]scale (Sinusoidal)
-Jkf[lon0/]scale (Eckert IV)
-Jk[s][lon0/]scale (Eckert VI)
-Jn[lon0/]scale (Robinson)
-Jr[lon0/]scale (Winkel Tripel)
-Jv[lon0/]scale (Van der Grinten)
-Jw[lon0/]scale (Mollweide)
NON-GEOGRAPHICAL PROJECTIONS:
-Jp[a]scale[/origin][r|z] (Polar coordinates (theta,r))
-Jxx-scale[d|l|ppow|t|T][/y-scale[d|l|ppow|t|T]] (Linear, log,
and power scaling)
-R west, east, south, and north specify the Region of interest, and
you may specify them in decimal degrees or in
[+-]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, specify the name of an existing grid file and the
-R settings (and grid spacing, if applicable) are copied from
the grid.
-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
-E Sets the viewpoint's azimuth and elevation (for perspective
view) [180/90]. For frames used for animation, you may want to
append + to fix the center of your data domain (or specify a
particular world coordinate point with +wlon0/lat[/z]) which
will project to the center of your page size (or specify the
coordinates of the projected view point with +vx0/y0).
-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.
You must specify at least one of -W and -F.
OPTIONS
No space between the option flag and the associated arguments.
-A Flip the default byte-swap state (default assumes data have a
bigendian byte-order).
-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).
-I Fill negative rather than positive excursions.
-K More PostScript code will be appended later [Default terminates
the plot system].
-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 Selects Overlay plot mode [Default initializes a new plot sys‐
tem].
-P Selects Portrait plotting mode [Default is Landscape, see gmtde‐
faults to change this].
-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.
-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.
-V Selects verbose mode, which will send progress reports to stderr
[Default runs "silently"].
-X Multiply trace locations by scale before plotting.
-Y Override sample interval in reel header.
-Z Do not plot traces with zero rms amplitude.
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
pssegyz wa1.segy -JX 5/-5 -D 1 -Jz 0.05 -E 180/5 -R 0/100/0/10/0/10 -C
3 -N -S o -W -F black > 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 ALSOGMT(1), pssegy(1)GMT 4.5.14 1 Nov 2015 PSSEGYZ(1)
