NAME

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

SYNOPSIS

       pswiggle  [  table  ]  parameters west/east/south/north[/zmin/zmax][r] scale [ azimuth ] [
       [p|s]parameters ] [ center ] [ [+|-|=]fill ] [ z|Zparameters ] [ fix_az ] [  ] [  ] [ -P ]
       [  [x]lon0/lat0/length[/units]  ] [ pen ] [ [just/dx/dy/][c|label] ] [ [level] ] [ pen ] [
       x_offset ] [ y_offset ] [ -bi<binary> ] [ -ccopies ] [  -di<nodata>  ]  [  -f<flags>  ]  [
       -g<gaps> ] [ -h<headers> ] [ -i<flags> ] [ -p<flags> ] [ -t<transp> ] [ -:[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. 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.

       -R[unit]xmin/xmax/ymin/ymax[r] (more ...)
              Specify the region of interest.

       For perspective view p, optionally append /zmin/zmax. (more ...)

       -Zscale
              Gives anomaly scale in data-units/distance-unit.

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.

       -Aazimuth
              Sets the preferred positive azimuth. Positive wiggles will "gravitate" towards that
              direction.

       -B[p|s]parameters (more ...)
              Set map boundary intervals.

       -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].

       -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].

       -ccopies (more ...)
              Specify number of plot copies [Default is 1].

       -dinodata (more ...)
              Replace input columns that equal nodata with NaN.

       -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 (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
              use just -).

       -+ 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  options,  then
              exits.

       --version
              Print GMT version and exit.

       --show-datadir
              Print full path to GMT share directory and exit.

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

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

       and plot this data set instead.

SEE ALSO

       gmt, gmtcolors, filter1d, psbasemap, splitxyz

COPYRIGHT

       2015, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe