pswiggle(1) GMT pswiggle(1)
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 con-
secutive (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 a|)
Select map projection.
-Rxmin/xmax/ymin/ymax[+r][+uunit] (more a|)
Specify the region of interest.
For perspective view p, optionally append /zmin/zmax. (more a|)
-Zscale[units]
Gives anomaly scale in data-units/distance-unit, where dis-
tance-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
agravitatea 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 a|)
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 pos-
itive 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 a|)
Set z-axis scaling; same syntax as -Jx.
-K (more a|)
Do not finalize the PostScript plot.
-O (more a|)
Append to existing PostScript plot.
-P (more a|)
Select aPortraita 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 a|)
Draw GMT time stamp logo on plot.
-V[level] (more a|)
Select verbosity level [c].
-Wpen
-bi[ncols][t] (more a|)
Select native binary input. [Default is 3 input columns].
-dinodata (more a|)
Replace input columns that equal nodata with NaN.
-e[~]^<i>apattern^<i>a | -e[~]/regexp/[i] (more a|)
Only accept data records that match the given pattern.
-f[i|o]colinfo (more a|)
Specify data types of input and/or output columns.
-g[a]x|y|d|X|Y|D|[col]z[+|-]gap[u] (more a|)
Determine data gaps and line breaks.
-h[i|o][n][+c][+d][+rremark][+rtitle] (more a|)
Skip or produce header record(s).
-icols[+l][+sscale][+ooffset][,^<i>a|] (more a|)
Select input columns and transformations (0 is first column).
-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.
-:[i|o] (more a|)
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 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 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 direc-
tion. To instead enforce a fixed azimuth of 45 for the positive wig-
gles, 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 anawka 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(1), gmtcolors(5), filter1d(1), psbasemap(1), splitxyz(1)
COPYRIGHT
2017, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
5.4.2 Jun 24, 2017 pswiggle(1)
gmt5 5.4.2 - Generated Thu Jun 29 16:03:38 CDT 2017