Provided by: gmt-common_5.4.5+dfsg-1_all bug


       pswiggle - Plot z = f(x,y) anomalies along tracks


       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.


       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


       -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 ...)

              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).


       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.

              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

       -B[p|s]parameters (more ...)
              Set map boundary frame and axes attributes.

              Subtract center from the data set before plotting [0].

              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.

              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

       -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.

              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].


       -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.


       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 >

       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 >


       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; }' | 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 }' | filter1d -Fb5 -N4/0 \
              --FORMAT_FLOAT_OUT=%.12g >

       which performs a 5-point boxcar filter, and plot this data set instead.


       gmt, gmtcolors, filter1d, psbasemap, splitxyz


       2019, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe