Provided by: gmt-common_5.4.5+dfsg-2_all bug


       hotspotter - Create CVA image from seamount locations


       hotspotter [tables]  -Erotfile  -GCVAgrid
        -Rregion  [   -Nupper_age  ] [  -S ] [  -T ] [  -V[level] ] [ -bibinary ] [ -dinodata ] [
       -eregexp ] [ -hheaders ] [ -iflags ] [ -oflags ] [ -:[i|o] ]

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


       hotspotter reads (longitude, latitude, amplitude, radius, age)  records  from  tables  [or
       standard input] and calculates flowlines using the specified stage or total reconstruction
       rotations. These flowlines are convolved with the shape of the seamount (using a  Gaussian
       shape  given  amplitude  and  radius  = 6 sigma) and added up to give a Cumulative Volcano
       Amplitude grid (CVA). See option -: on how to read (latitude,longitude,...) files.


       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.

              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.

              Specify name for output grid file.

              x_inc [and optionally y_inc] is the  grid  spacing.  Optionally,  append  a  suffix
              modifier. Geographical (degrees) coordinates: Append m to indicate arc minutes or s
              to indicate arc seconds. If one of the units e,  f,  k,  M,  n  or  u  is  appended
              instead,  the  increment  is assumed to be given in meter, foot, km, Mile, nautical
              mile or US survey foot, respectively, and  will  be  converted  to  the  equivalent
              degrees  longitude  at the middle latitude of the region (the conversion depends on
              PROJ_ELLIPSOID). If y_inc is given but set to 0 it will be reset  equal  to  x_inc;
              otherwise  it  will  be  converted  to  degrees latitude. All coordinates: If +e is
              appended then the corresponding max x (east) or y (north) may be slightly  adjusted
              to  fit  exactly  the  given  increment  [by  default the increment may be adjusted
              slightly to fit the given domain]. Finally, instead of giving an increment you  may
              specify  the  number  of  nodes  desired  by  appending  +n to the supplied integer
              argument; the increment is then recalculated from  the  number  of  nodes  and  the
              domain.  The  resulting  increment  value  depends  on  whether you have selected a
              gridline-registered or pixel-registered grid;  see  App-file-formats  for  details.
              Note:  if -Rgrdfile is used then the grid spacing has already been initialized; use
              -I to override the values.

              west, east, south, and north specify the region of interest, and  you  may  specify
              them  in decimal degrees or in [±]dd:mm[][W|E|S|N] format Append +r if lower
              left and upper right  map  coordinates  are  given  instead  of  w/e/s/n.  The  two
              shorthands  -Rg  and  -Rd stand for global domain (0/360 and -180/+180 in longitude
              respectively, with -90/+90 in latitude).  Alternatively  for  grid  creation,  give
              Rcodelon/lat/nx/ny,  where  code is a 2-character combination of L, C, R (for left,
              center, or right) and T, M, B for top, middle, or bottom. e.g., BL for lower  left.
              This  indicates  which  point on a rectangular region the lon/lat coordinate refers
              to, and the grid dimensions nx and ny with grid spacings via -I is used  to  create
              the corresponding region.  Alternatively, specify the name of an existing grid file
              and the -R settings (and grid spacing, if applicable) are  copied  from  the  grid.
              Appending  +uunit  expects projected (Cartesian) coordinates compatible with chosen
              -J and we inversely project to determine actual rectangular geographic region.  For
              perspective  view  (-p), optionally append /zmin/zmax.  In case of perspective view
              (-p), a z-range (zmin, zmax) can be appended to indicate the third dimension.  This
              needs to be done only when using the -Jz option, not when using only the -p option.
              In the latter case a perspective view of  the  plane  is  plotted,  with  no  third


              Modify  the  sampling interval along flowlines. Default [0.5] gives approximately 2
              points within each grid box.  Smaller  factors  gives  higher  resolutions  at  the
              expense of longer processing time.

              Set  the upper age to assign seamounts whose crustal age is unknown (i.e., NaN) [no
              upper age].

       -S     Normalize the resulting CVA grid to percentages of the CVA maximum.

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

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

       -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).

       -ocols[,...] (more ...)
              Select output columns (0 is first column).

       -r (more ...)
              Set pixel node registration [gridline].

       -:[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 create a CVA image from the Pacific (x,y,z,r,t) data in the file seamounts.d, using the
       DC85.d Euler poles, run

              gmt hotspotter seamounts.d -EDC85.d -R130/260/-66/60 -I10m -N145 -T -V

       This file can then be plotted with grdimage.


       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, grdimage, grdrotater,  grdspotter,  project,  mapproject,  backtracker,  gmtpmodeler,
       grdpmodeler, grdrotater, originator


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

       Wessel,  P.,  2008,  Hotspotting:  Principles  and  properties  of  a plate tectonic Hough
       transform, Geochem. Geophys. Geosyst. 9(Q08004): doi:10.1029/2008GC002058.


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