manpagez: man pages & more
man hotspotter(1)
Home | html | info | man
hotspotter(1)                         GMT                        hotspotter(1)




NAME

       hotspotter - Create CVA image from seamount locations


SYNOPSIS

       hotspotter [tables]  -Erotfile  -GCVAgrid
        -Iincrement
        -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.


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  Vol-
       cano  Amplitude grid (CVA). See option -: on how to read (latitude,lon-
       gitude,a|) 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 rota-
              tion cannot be found.

       -GCVAgrid
              Specify name for output grid file.

       -Ixinc[unit][+e|n][/yinc[unit][+e|n]]
              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,  nau-
              tical  mile  or  US  survey foot, respectively, and will be con-
              verted to the equivalent degrees longitude at the  middle  lati-
              tude  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 coordi-
              nates: 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 recalcu-
              lated from the number of nodes and  the  domain.  The  resulting
              increment  value  depends  on  whether you have selected a grid-
              line-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.

       -Rwest/east/south/north[/zmin/zmax][+r][+uunit]
              west, east, south, and north specify the region of interest, and
              you    may    specify    them   in   decimal   degrees   or   in
              [A+-]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. Appending +uunit expects projected (Carte-
              sian)  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 fac-
              tors gives higher resolutions at the expense of longer  process-
              ing 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 maxi-
              mum.

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

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

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

       -dinodata (more a|)
              Replace input columns that equal nodata with NaN.

       -e[~]^<i>apattern^<i>a | -e[~]/regexp/[i] (more a|)
              Only accept data records that match the given pattern.

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

       -icols[+l][+sscale][+ooffset][,^<i>a|] (more a|)
              Select input columns and transformations (0 is first column).

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

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

       -:[i|o] (more a|)
              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 explana-
              tion 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.


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  coordi-
       nates.  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_Earth-
       Byte_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(1), grdimage(1), grdrotater(1), grdspotter(1), project(1),
       mapproject(1),  backtracker(1), gmtpmodeler(1), grdpmodeler(1),
       grdrotater(1), originator(1)


REFERENCES

       Wessel,  P.,  1999,  aHotspottinga  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.


COPYRIGHT

       2017, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe



5.4.2                            Jun 24, 2017                    hotspotter(1)

gmt5 5.4.2 - Generated Thu Jun 29 13:42:59 CDT 2017
© manpagez.com 2000-2021
Individual documents may contain additional copyright information.