NAME

       hotspotter - Create CVA image from seamount flowlines

SYNOPSIS

       hotspotter       [infile(s)]       -Estage_file       -GCVAgrid       -Ixinc[unit][=|+][/yinc[unit][=|+]]
       -Rwest/east/south/north[r] [ -C ] [ -Dfactor ] [ -F ] [ -H[i][nrec] ] [ -Nupper_age ] [ -S ] [ -T ] [  -V
       ] [ -:[i|o] ] [ -bi[s|S|d|D[ncol]|c[var1/...]] ]

DESCRIPTION

       hotspotter  reads (longitude, latitude, amplitude, radius, age) records from infiles  [or standard input]
       and calculates flowlines using the specified stage pole (Euler) 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.
            No  space between the option flag and the associated arguments.  Use upper case for the option flags
       and lower case for modifiers.

       infile(s)
              Data file(s) to be processed.  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 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 -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 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.

       -G     Specify name for output grid file.

       -I     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 c to indicate arc seconds.
              If  one  of  the  units e, k, i, or n is appended instead, the increment is assumed to be given in
              meter, km, miles, or nautical miles, respectively, and will be converted to the equivalent degrees
              longitude  at  the middle latitude of the region (the conversion depends on 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 = 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 + 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  Appendix  B  for
              details.   Note:  if  -Rgrdfile  is used then grid spacing has already been initialized; use -I to
              override the values.

       -R     west, east, south, and north specify the Region of interest, and you may specify them  in  decimal
              degrees  or  in  [+-]dd:mm[:ss.xxx][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, specify
              the name of an existing grid file and the -R settings (and grid spacing, if applicable) are copied
              from the grid.

OPTIONS

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

       -D     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.

       -F     Force pixel registration [Default is grid registration].

       -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.

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

       -:     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.  Optionally, 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  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

       hotspotter seamounts.d -E DC85.d -G CVA.grd -R 130/260/-66/60 -I 10m -N 145 -T -V

       This file can then be plotted with grdimage.

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 --ELLIPSOID=sphere.

SEE ALSO

       GMT(1),   grdimage(1),   grdrotater(1),   grdspotter(1),   project(1),   mapproject(1),   backtracker(1),
       originator(1)

REFERENCES

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