xenial (1) hotspotter.1gmt.gz

Provided by: gmt-common_5.2.1+dfsg-3build1_all bug

NAME

       hotspotter - Create CVA image from seamount locations

SYNOPSIS

       hotspotter  [tables] rotfile CVAgrid increment region [ upper_age ] [  ] [  ] [ [level] ] [ -bi<binary> ]
       [ -di<nodata> ] [ -h<headers> ] [ -i<flags> ] [ -o<flags> ] [ -:[i|o] ]

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

DESCRIPTION

       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.

REQUIRED ARGUMENTS

       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.

       -Erotfile
              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.

       -GCVAgrid
              Specify name for output grid file.

       -Ixinc[unit][=|+][/yinc[unit][=|+]]
              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 = 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 App-file-formats for details. Note: if -Rgrdfile is used then the  grid
              spacing has already been initialized; use -I to override the values.

       -R[unit]west/east/south/north[/zmin/zmax][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 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. Using -Runit 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 dimension.

OPTIONAL ARGUMENTS

       -Dfactor
              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.

       -Nupper_age
              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.

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

       -icols[l][sscale][ooffset][,...] (more ...)
              Select input columns (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 use just -).

       -+ 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 options, then exits.

       --version
              Print GMT version and exit.

       --show-datadir
              Print full path to GMT share directory and exit.

GEODETIC VERSUS GEOCENTRIC COORDIINATES

       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.

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

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

       This file can then be plotted with grdimage.

NOTES

       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.

SEE ALSO

       gmt, grdimage, grdrotater, grdspotter, project, mapproject, backtracker, originator

REFERENCES

       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.

       2015, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe