Provided by: gmt-common_5.4.3+dfsg-1_all 
NAME
pswiggle - Plot z = f(x,y) anomalies along tracks
SYNOPSIS
pswiggle [ table ] -Jparameters -Rwest/east/south/north[/zmin/zmax][+r] -Zscale[units]
[ |-A|[*azimuth] ] [ -B[p|s]parameters ] [ -Ccenter ] [ -G[+|-|=]fill ] [ -Ifix_az ] [
-K ] [ -O ] [ -P ] [ -S[x]lon0/lat0/length[/units] ] [ -Tpen ] [ -U[stamp] ] [
-V[level] ] [ -Wpen ] [ -Xx_offset ] [ -Yy_offset ] [ -bibinary ] [ -dinodata ] [
-eregexp ] [ -fflags ] [ -ggaps ] [ -hheaders ] [ -iflags ] [ -pflags ] [ -ttransp ] [
-:[i|o] ]
Note: No space is allowed between the option flag and the associated arguments.
DESCRIPTION
pswiggle reads (x,y,z) triplets from files [or standard input] and plots z as a function
of distance along track. This means that two consecutive (x,y) points define the local
distance axis, and the local z axis is then perpendicular to the distance axis, forming a
right-handed coordinate system. The user may set a preferred positive anomaly plot
direction, and if the positive normal is outside the plus/minus 90 degree window around
the preferred direction, then 180 degrees are added to the direction. Either the positive
or the negative wiggle may be shaded. The resulting PostScript code is written to standard
output.
REQUIRED ARGUMENTS
-Jparameters (more …)
Select map projection.
-Rxmin/xmax/ymin/ymax[+r][+uunit] (more …)
Specify the region of interest.
For perspective view p, optionally append /zmin/zmax. (more …)
-Zscale[units]
Gives anomaly scale in data-units/distance-unit, where distance-unit is the
currently chosen unit specified by PROJ_LENGTH_UNIT. Alternatively, append a
distance-unit among the other choices (c|i|p).
OPTIONAL ARGUMENTS
table One or more ASCII (or binary, see -bi[ncols][type]) data table file(s) holding a
number of data columns. If no tables are given then we read from standard input.
-A[azimuth]
Sets the preferred positive azimuth. Positive wiggles will “gravitate” towards that
direction, i.e., azimuths of the normal direction to the track will be flipped into
the -90/+90 degree window centered on azimuth and that defines the positive wiggle
side. If no azimuth is given the no preferred azimuth is enforced. Default is
-A0.
-B[p|s]parameters (more …)
Set map boundary frame and axes attributes.
-Ccenter
Subtract center from the data set before plotting [0].
-G[+|-|=]fill
Set fill shade, color or pattern for positive and/or negative wiggles [Default is
no fill]. Optionally, prepend + to fill positive areas (this is the default
behavior). Prepend - to fill negative areas. Prepend = to fill both positive and
negative areas with the same fill.
-Ifix_az
Set a fixed azimuth projection for wiggles [Default uses track azimuth, but see
-A]. With this option, the calculated track-normal azimuths are overridden by
fixed_az.
-Jz|Zparameters (more …)
Set z-axis scaling; same syntax as -Jx.
-K (more …)
Do not finalize the PostScript plot.
-O (more …)
Append to existing PostScript plot.
-P (more …)
Select “Portrait” plot orientation.
-S[x]lon0/lat0/length[/units]
Draws a simple vertical scale centered on lon0/lat0. Use -Sx to specify cartesian
coordinates instead. length is in z units, append unit name for labeling.
FONT_ANNOT_PRIMARY is used as font.
-Tpen Draw track [Default is no track]. Append pen attributes to use [Defaults: width =
0.25p, color = black, style = solid].
-U[[just]/dx/dy/][c|label] (more …)
Draw GMT time stamp logo on plot.
-V[level] (more …)
Select verbosity level [c].
-Wpen
-bi[ncols][t] (more …)
Select native binary input. [Default is 3 input columns].
-dinodata (more …)
Replace input columns that equal nodata with NaN.
-e[~]”pattern” | -e[~]/regexp/[i] (more …)
Only accept data records that match the given pattern.
-f[i|o]colinfo (more …)
Specify data types of input and/or output columns.
-g[a]x|y|d|X|Y|D|[col]z[+|-]gap[u] (more …)
Determine data gaps and line breaks.
-h[i|o][n][+c][+d][+rremark][+rtitle] (more …)
Skip or produce header record(s).
-icols[+l][+sscale][+ooffset][,…] (more …)
Select input columns and transformations (0 is first column).
-p[x|y|z]azim[/elev[/zlevel]][+wlon0/lat0[/z0]][+vx0/y0] (more …)
Select perspective view.
-t[transp] (more …)
Set PDF transparency level in percent.
-:[i|o] (more …)
Swap 1st and 2nd column on input and/or output.
-^ 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 explanation 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 magnetic anomaly stored in the file track.xym along track @ 1000 nTesla/cm
(after removing a mean value of 32000 nTesla), using a 15-cm-wide Polar Stereographic map
ticked every 5 degrees in Portrait mode, with positive anomalies in red on a blue track of
width 0.25 points, use
gmt pswiggle track.xym -R-20/10/-80/-60 -JS0/90/15c -Z1000 -B5 \
-C32000 -P -Gred -T0.25p,blue -S1000 -V > track_xym.ps
and the positive anomalies will in general point in the north direction. To instead
enforce a fixed azimuth of 45 for the positive wiggles, we add -I and obtain
gmt pswiggle track.xym -R-20/10/-80/-60 -JS0/90/15c -Z1000 -B5 \
-C32000 -P -Gred -I45 -T0.25p,blue -S1000 -V > track_xym.ps
BUGS
Sometimes the (x,y) coordinates are not printed with enough significant digits, so the
local perpendicular to the track swings around a lot. To see if this is the problem, you
should do this:
awk '{ if (NR > 1) print atan2(y-$1, x-$2); y=$1; x=$2; }' yourdata.xyz | more
(note that output is in radians; on some machines you need “nawk” to do this). Then if
these numbers jump around a lot, you may do this:
awk '{ print NR, $0 }' yourdata.xyz | filter1d -Fb5 -N4/0 \
--FORMAT_FLOAT_OUT=%.12g > smoothed.xyz
which performs a 5-point boxcar filter, and plot this data set instead.
SEE ALSO
gmt, gmtcolors, filter1d, psbasemap, splitxyz
COPYRIGHT
2018, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe