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NAME

       pswiggle - Plot anomaly along track on a map

SYNOPSIS

       pswiggle  xyz_files  -Jparameters  -Rwest/east/south/north[r]  -Zscale  [  -Aazimuth  ]  [ -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 UNIT/degree, 1:xxxxx, or width in UNIT (upper case modifier).
              UNIT  is  cm,  inch,  or m, depending on the MEASURE_UNIT setting in .gmtdefaults, but this can be
              overridden on the command line by appending the c, i, or m to the scale/width value.

              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, with Equator as y = 0)
              -Jtlon0/lat0/scale (TM - Transverse Mercator, set origin)
              -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/[slat/]scale (General Stereographic)

              CONIC PROJECTIONS:

              -Jblon0/lat0/lat1/lat2/scale (Albers)
              -Jdlon0/lat0/lat1/lat2/scale (Equidistant)
              -Jllon0/lat0/lat1/lat2/scale (Lambert)

              MISCELLANEOUS PROJECTIONS:

              -Jhlon0/scale (Hammer)
              -Jilon0/scale (Sinusoidal)
              -Jk[f|s]lon0/scale (Eckert IV (f) and VI (s))
              -Jnlon0/scale (Robinson)
              -Jrlon0/scale (Winkel Tripel)
              -Jvlon0/scale (Van der Grinten)
              -Jwlon0/scale (Mollweide)

              NON-GEOGRAPHICAL PROJECTIONS:

              -Jp[a]scale[/origin] (polar (theta,r) coordinates, optional a for azimuths and offset theta [0])
              -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/distance-unit.

OPTIONS

       No space between the option flag and the associated arguments.

       -A     Sets the preferred positive azimuth. 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, each
              in 0-255).

       -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].

       -bo    Selects binary output. Append s for single precision [Default is double].

       -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. Optionally, append a  label,  or  c
              (which  will  plot the command string.). The GMT parameters UNIX_TIME and UNIX_TIME_POS can affect
              the appearance; see the gmtdefaults man page for details.

       -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).  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)].  Applies to geographic coordinates only.

       -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/cm (after removing  a
       mean  value  of  32000  Tesla),  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, try

       pswiggle track.xym -R-20/10/-80/-60 -JS0/90/15c -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(1gmt), filter1d(1gmt), psbasemap(1gmt), splitxyz(1gmt)

                                                   1 Jan 2004                                        PSWIGGLE(l)