NAME

      pswiggle - Plot anomaly along track on a map

SYNOPSIS

      pswiggle xyz_files -Jparameters -Rwest/east/south/north[r] -Zscale [
      -Adirection ] [ -Btickinfo ] [ -Ccenter ] [ -Dgap ] [
      -Eazimuth/elevation ] [ -Gfillrgb ] [ -H[nrec] ] [ -Ifix_az ] [ -K ] [
      -M[flag] ] [ -N ] [ -O ] [ -P ] [ -S[x]lon0/lat0/length[units] ] [
      -Ttrack_pen ] [ -U[/dx/dy/][label] ] [ -V  ] [ -Wwiggle_pen ] [ -Xx-
      shift ] [ -Yy-shift ] [ -ccopies ] [ -: ] [ -bi[s][n] ]

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.

      files
           List one or more file-names. If no files are given, pswiggle will
           read standard input.

      -J   Selects the map projection. Scale is inch/degree, 1:xxxxx, or
           width in inch (upper case modifier).

           CYLINDRICAL PROJECTIONS:

           -Jclon0/lat0/scale (Cassini)
           -Jjlon0/scale (Miller)
           -Jmscale (Mercator - Greenwich and Equator as origin)
           -Jmlon0/lat0/scale (Mercator - Give meridian and standard
           parallel)
           -Joalon0/lat0/azimuth/scale (Oblique Mercator - point and
           azimuth)
           -Joblon0/lat0/lon1/lat1/scale (Oblique Mercator - two points)
           -Joclon0/lat0/lonp/latp/scale (Oblique Mercator - point and pole)
           -Jqlon0/scale (Equidistant Cylindrical Projection (Plate Carree))
           -Jtlon0/scale (TM - Transverse Mercator)
           -Juzone/scale (UTM - Universal Transverse Mercator)
           -Jylon0/lats/scale (Basic Cylindrical Projection)

           AZIMUTHAL PROJECTIONS:

           -Jalon0/lat0/scale (Lambert).
           -Jelon0/lat0/scale (Equidistant).
           -Jflon0/lat0/horizon/scale (Gnomonic).
           -Jglon0/lat0/scale (Orthographic).
           -Jslon0/lat0/scale (General Stereographic)

           CONIC PROJECTIONS:

           -Jblon0/lat0/lat1/lat2/scale (Albers)
           -Jllon0/lat0/lat1/lat2/scale (Lambert)

           MISCELLANEOUS PROJECTIONS:

           -Jhlon0/scale (Hammer)
           -Jilon0/scale (Sinusoidal)
           -Jklon0/scale (Eckert VI)
           -Jnlon0/scale (Robinson)
           -Jrlon0/scale (Winkel Tripel)
           -Jwlon0/scale (Mollweide)

           NON-GEOGRAPHICAL PROJECTIONS:

           -Jpscale (Linear projection for polar (theta,r) coordinates)
           -Jxx-scale[l|ppow][/y-scale[l|ppow]] (Linear, log, and power
           scaling)
           More details can be found in the psbasemap manpages.

      -R   west, east, south, and north specify the Region of interest.  To
           specify boundaries in degrees and minutes [and seconds], use the
           dd:mm[:ss] format.  Append r if lower left and upper right map
           coordinates are given instead of wesn.

      -Z   Gives anomaly scale in data-units/inch.

OPTIONS

      No space between the option flag and the associated arguments.

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

      -B   Sets map boundary tickmark intervals. See psbasemap for details.

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

      -D   Means there is a data gap if 2 consecutive points are more than
           gap distance units apart.  For longitude/latitude data gap is in
           km, else it is in the user's units.

      -E   Sets the viewpoint's azimuth and elevation [180/90]

      -G   Set fill of positive wiggles. [Default is black] Specify the
           shade (0-255) or color (r/g/b), or -Gpdpi/pattern, where pattern
           gives the number of the built-in pattern (1-90) OR the name of a
           Sun 1-, 8-, or 24-bit raster file.  dpi sets the resolution of
           the image.  For 1-bit rasters: use -GP for inverse video, or
           append :Fr/g/b[B[r/g/b]] to specify fore- and background colors.
           See GMT Cookbook & Technical Reference Appendix E for information
           on individual patterns.

      -H   Input file(s) has Header record(s).  Number of header records can
           be changed by editing your .gmtdefaults file.  If used, GMT
           default is 1 header record.

      -I   Set a fixed azimuth projection for wiggles [Default uses track
           azimuth, but see -A].

      -K   More PostScript code will be appended later [Default terminates
           the plot system].

      -M   Multiple segment file.  Segments are separated by a record whose
           first character is flag.  [Default is '>'].

      -N   Paint negative wiggles instead of positive [Default].

      -O   Selects Overlay plot mode [Default initializes a new plot
           system].

      -P   Selects Portrait plotting mode [GMT Default is Landscape, see
           gmtdefaults to change this].

      -S   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

      -T   Draw track  [Default is no track].  Append pen attributes to use
           [Defaults: width = 1, color = 0/0/0, texture = solid].

      -U   Draw Unix System time stamp on plot.  User may specify where the
           lower left corner of the stamp should fall on the page relative
           to lower left corner of plot in inch [Default is (-0.75i/-
           0.75i)].  Optionally, append a label, or c (which will plot the
           command string.)

      -V   Selects verbose mode, which will send progress reports to stderr
           [Default runs "silently"].

      -W   Draw wiggle outline  [Default is no outline].  Append pen
           attributes to use [Defaults: width = 1, color = 0/0/0, texture =
           solid].

      -X -Y
           Shift origin of plot by (x-shift,y-shift) inch  [Default is
           (a1i,a1i) for new plots, (0,0) for overlays].  Prepend a for
           absolute coordinates; the default (r) will reset plot origin.


      -:   Toggles between (longitude,latitude) and (latitude,longitude)
           input/output.  [Default is (longitude,latitude)].

      -c   Specifies the number of plot copies. [Default is 1]

      -bi  Selects binary input.  Append s for single precision [Default is
           double].  Append n for the number of columns in the binary
           file(s).  [Default is 3 input columns].

EXAMPLES

      To plot the magnetic anomaly stored in the file track.xym along track
      @ 1000 nTesla/inch (after removing a mean value of 32000 Tesla), using
      a 5-inch-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, try

      pswiggle track.xym -R-20/10/-80/-60 -JS0/90/5i -Z1000 -B5 -P -G255/0/0
      -T0.25p/0/0/255 -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:

      gmtset D_FORMAT %.12lg
      awk '{ print NR, $0 }' yourdata.xyz | filter1d -Fb5 -N4/0 >
      smoothed.xyz

      and plot this data set instead.

SEE ALSO

      gmt, filter1d, psbasemap, splitxyz