ORIGINATOR(1gmt)					       Generic Mapping Tools						  ORIGINATOR(1gmt)

NAME

       originator - Associate seamounts with hotspot point sources

SYNOPSIS

       originator  [infile(s)] -Estage_file -Fhs_file [ -C ] [ -Dd_km ] [ -H[i][nrec] ] [ -L[flag] ] [ -Nupper_age ] [ -Qr/t ] [ -S[n_hs] ] [ -T ]
       [ -V ]  -Wmaxdist ] [ -Z ] [ -:[i|o] ] [ -bi[s|S|d|D[ncol]|c[var1/...]] ]

DESCRIPTION

       originator reads (longitude, latitude, height, radius, crustal_age) records from infiles [or standard input] and uses  the  given  Absolute
       Plate  Motion (APM) stage poles and the list of hotspot locations to determine the most likely origin (hotspot) for each seamount.  It does
       so by calculating flowlines back in time and determining the closest approach to all hotspots.  The output consists of  the  input  records
       with  four  additional fields added for each of the n_hs closest hotspots.  The four fields are the hotspot id (e.g., HWI), the stage id of
       the flowline segment that came closest, the pseudo-age of the seamount, and the closest distance to the hotspot (in km).  See option -:	on
       how to read (latitude, longitude,height, radius, crustal_age) files.
	    No space between the option flag and the associated arguments.  Use upper case for the option flags and lower case for modifiers.

       infile(s)
	      Seamount data file(s) to be analyzed.  If not given, standard input is read.

       -E     Give  file with rotation parameters.  This file must contain one record for each rotation; each record must be of the following for-
	      mat:

		   lon lat tstart [tstop] angle [ khat a b c d e f g df ]

	      where tstart and tstop are in Myr and lon lat angle are in degrees.  tstart and tstop are the ages of the old and young  ends  of  a
	      stage.   If  -C is set then a total reconstruction rotation is expected and tstop is implicitly set to 0 and should not be specified
	      in the file.  If a covariance matrix C for the rotation is available it must be specified in a format using the nine optional  terms
	      listed in brackets.  Here, C = (g/khat)*[ a b d; b c e; d e f ] which shows C made up of three row vectors.  If the degrees of free-
	      dom (df) in fitting the rotation is 0 or not given it is set to 10000.  Blank lines and records whose first column contains  #  will
	      be ignored.

       -F     Give  file  with hotspot locations.  This file must contain one record for each hotspot to be considered; each record must be of the
	      following format:

		   lon lat hs_abbrev hs_id r t_off t_on create fit plot name

	      E.g., for Hawaii this may look like

	      205  20	HWI  1	  25   0    90	 Y    Y    Y	Hawaii

	      Most applications only need the first 4 columns which thus represents the minimal hotspot information record type.  The abbreviation
	      may be maximum 3 characters long.  The id must be an integer from 1-32.  The positional uncertainty of the hotspot is given by r (in
	      km).  The t_off and t_on variables are used to indicate the active time-span of the hotspot.  The create, fit, and  plot	indicators
	      are  either Y or N and are used by some programs to indicate if the hotspot is included in the ID-grids used to determine rotations,
	      if the hotspot chain will be used to determine rotations, and if the hotspot should be included in various plots.   The  name  is  a
	      32-character maximum text string with the full hotspot name.  Blank lines and records whose first column contains # will be ignored.

OPTIONS

       -C     Expect  Total Reconstruction Rotations rather than Forward Stage Rotations [Default].  File format is similar to the stage pole for-
	      mat except that the tstart column is not present (assumed to be 0 Ma).

       -D     Sets the flowline sampling interval in km.  [Default is 5].

       -H     Input file(s) has header record(s).  If used, the default number of header records is N_HEADER_RECS.  Use -Hi  if  only  input  data
	      should  have header records [Default will write out header records if the input data have them]. Blank lines and lines starting with
	      # are always skipped.

       -L     Output closest approach for nearest hotspot only (ignores -S).  Choose -Lt for (time, dist, z) [Default], -Lw for (omega, dist,  z),
	      and -Ll for (lon, lat, time, dist, z).  Normally, dist is in km; use upper case modifiers TWL to get dist in spherical degrees.

       -N     Set the maximum age to extend the oldest stage back in time [no extension].

       -Q

       INput files only has (x,y,z); specify constant values for r,t that
	      will be implied for each record.	-S Set the number of closest hotspots to report [Default is 1].

       -T     Truncate seamount ages exceeding the upper age set with -N [no truncation].

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

       -W     Only report those seamounts whose flowlines came within maxdist to any hotspot [Default reports all seamounts].

       -Z     Use the hotspot ID number rather than the name tag in output records.

       -:     Toggles  between (longitude,latitude) and (latitude,longitude) input and/or output.  [Default is (longitude,latitude)].  Append i to
	      select input only or o to select output only.  [Default affects both].

       -bi    Selects binary input.  Append s for single precision [Default is d (double)].  Uppercase S or D will force  byte-swapping.   Option-
	      ally,  append ncol, the number of columns in your binary input file if it exceeds the columns needed by the program.  Or append c if
	      the input file is netCDF. Optionally, append var1/var2/... to specify the variables to be read.  [Default is 5 input columns].

EXAMPLES

       To find the likely (hotspot) origins of the seamounts represented by the (x,y,z,r,tc) points in the  file  seamounts.d,	using  the  DC85.d
       Euler poles and the pac_hs.d list of possible hotspots, and report the 2 most likely hotspot candidates for each seamount, run

       originator seamounts.d -S2 -EDC85.d -Fpac_hs.d > origins.d

COORDINATES

       Data coordinates are assumed to be geodetic and will automatically be converted to geocentric before spherical rotations are performed.	We
       convert back to geodetic coordinates for output.  Note: If your data already are geocentric, you can avoid the conversion by using --ELLIP-
       SOID=sphere.

SEE ALSO

       GMT(1), project(1), grdrotater(1), grdspotter(1), mapproject(1), backtracker(1), hotspotter(1)

REFERENCES

       Wessel, P., 1999, "Hotspotting" tools released, EOS Trans. AGU, 80(29), p. 319.

GMT 4.5.7							    15 Jul 2011 						  ORIGINATOR(1gmt)