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


       originator - Associate seamounts with nearest hotspot point sources


       originator [ tables ]  -E[+]rotfile
        -F[+]hs_file  [  -Dd_km ] [  -L[flag] ] [  -Nupper_age ] [  -Qr/t ] [  -S[n_hs] ] [  -T ]
       [  -V[level] ] [  -Wmaxdist ] [  -Z ] [ -bibinary ] [ -dinodata ] [ -eregexp ] [ -hheaders
       ] [ -iflags ] [ -:[i|o] ]

       Note: No space is allowed between the option flag and the associated arguments.


       originator  reads  (longitude,  latitude, height, radius, crustal_age) records from tables
       [or standard input] and uses  the  given  Absolute  Plate  Motion  (APM)  stage  or  total
       reconstruction  rotation  file  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.


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

              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 tstop is not present in
              the record then a total reconstruction rotation is expected and tstop is implicitly
              set  to  0  and  should  not  be specified for any of the records 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  freedom
              (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. You may prepend a leading  +
              to  the filename to indicate you wish to invert the rotations.  Alternatively, give
              the filename composed of two plate IDs separated by a hyphen (e.g., PAC-MBL) and we
              will instead extract that rotation from the GPlates rotation database. We return an
              error if the rotation cannot be  found.  Prepend  +  if  you  want  to  invert  the
              rotations prior to use.

       -Ffile 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. Prepend + if we should
              look for hotspot drift tables whose name must be  hs_abbrev_drift.txt.  Such  files
              may  be  located in the current directory, the same directory as hs_file, or in the
              directories pointed to by GMT_DATADIR. If found then we interpolate to get  hotspot
              location as a function of time [fixed].


       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.

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

              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.

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

       -Qr/t  Input  files only has (x,y,z); specify constant values for r,t that will be implied
              for each record.

              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[level] (more ...)
              Select verbosity level [c].

              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.

       -bi[ncols][t] (more ...)
              Select native binary input. [Default is 5 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.

       -V[level] (more ...)
              Select verbosity level [c].

       -icols[+l][+sscale][+ooffset][,...] (more ...)
              Select input columns and transformations (0 is first column).

       -:[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.


       All spherical rotations are applied to geocentric coordinates.  This means  that  incoming
       data  points  and grids are considered to represent geodetic coordinates and must first be
       converted  to  geocentric  coordinates.  Rotations  are  then  applied,  and   the   final
       reconstructed  points  are  converted back to geodetic coordinates.  This default behavior
       can be bypassed if the ellipsoid setting PROJ_ELLIPSOID is changed to Sphere.


       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

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

       To determine the predicted age of a seamount, distances to the closest hotspot,  and  echo
       the observed age given its location, observed age, and a rotation model, try

              echo "1.55 -8.43 52.3" | gmt originator -FONeill_2005_hotspots.txt \
              -EOMS2005_APM_fixed.txt -Q1/120 -Lt

       where  52.3 Ma is observed age. The output is 70 -95.486 52.3. To repeat the same exercise
       with a moving hotspot model, try

              echo "1.55 -8.43 52.3" | gmt originator -F+ONeill_2005_hotspots.txt \
              -EOMS2005_APM_smooth.txt -Q1/120 -Lt

       Now the output is 80 -213.135 52.3. Negative distances means the closest approach was east
       of the hotspot.


       GMT  distributes the EarthByte rotation model Global_EarthByte_230-0Ma_GK07_AREPS.rot.  To
       use an alternate rotation file, create an environmental parameters named GPLATES_ROTATIONS
       that points to an alternate rotation file.


       gmt,  grdrotater,  grdspotter, project, mapproject, backtracker, gmtpmodeler, grdpmodeler,
       grdrotater, hotspotter


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


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