1HOTSPOTTER(1) GMT HOTSPOTTER(1)
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6 hotspotter - Create CVA image from seamount locations
7
9 hotspotter [tables] -Erotfile -GCVAgrid
10 -Iincrement
11 -Rregion [ -Nupper_age ] [ -S ] [ -T ] [ -V[level] ] [ -bibinary ]
12 [ -dinodata ] [ -eregexp ] [ -hheaders ] [ -iflags ] [ -oflags ] [
13 -:[i|o] ]
14 Note: No space is allowed between the option flag and the associated
16 arguments.
17
19 hotspotter reads (longitude, latitude, amplitude, radius, age) records
20 from tables [or standard input] and calculates flowlines using the
21 specified stage or total reconstruction rotations. These flowlines are
22 convolved with the shape of the seamount (using a Gaussian shape given
23 amplitude and radius = 6 sigma) and added up to give a Cumulative Vol‐
24 cano Amplitude grid (CVA). See option -: on how to read (latitude,lon‐
25 gitude,...) files.
26
28 table One or more ASCII (or binary, see -bi[ncols][type]) data table
29 file(s) holding a number of data columns. If no tables are given
30 then we read from standard input.
31 -Erotfile
33 Give file with rotation parameters. This file must contain one
34 record for each rotation; each record must be of the following
35 format:
36 lon lat tstart [tstop] angle [ khat a b c d e f g df ]
38 where tstart and tstop are in Myr and lon lat angle are in
40 degrees. tstart and tstop are the ages of the old and young ends
41 of a stage. If tstop is not present in the record then a total
42 reconstruction rotation is expected and tstop is implicitly set
43 to 0 and should not be specified for any of the records in the
44 file. If a covariance matrix C for the rotation is available it
45 must be specified in a format using the nine optional terms
46 listed in brackets. Here, C = (g/khat)*[ a b d; b c e; d e f ]
47 which shows C made up of three row vectors. If the degrees of
48 freedom (df) in fitting the rotation is 0 or not given it is set
49 to 10000. Blank lines and records whose first column contains #
50 will be ignored. You may prepend a leading + to the filename to
51 indicate you wish to invert the rotations. Alternatively, give
52 the filename composed of two plate IDs separated by a hyphen
53 (e.g., PAC-MBL) and we will instead extract that rotation from
54 the GPlates rotation database. We return an error if the rota‐
55 tion cannot be found.
56 -GCVAgrid
58 Specify name for output grid file.
59 -Ixinc[unit][+e|n][/yinc[unit][+e|n]]
61 x_inc [and optionally y_inc] is the grid spacing. Optionally,
62 append a suffix modifier. Geographical (degrees) coordinates:
63 Append m to indicate arc minutes or s to indicate arc seconds.
64 If one of the units e, f, k, M, n or u is appended instead, the
65 increment is assumed to be given in meter, foot, km, Mile, nau‐
66 tical mile or US survey foot, respectively, and will be con‐
67 verted to the equivalent degrees longitude at the middle lati‐
68 tude of the region (the conversion depends on PROJ_ELLIPSOID).
69 If y_inc is given but set to 0 it will be reset equal to x_inc;
70 otherwise it will be converted to degrees latitude. All coordi‐
71 nates: If +e is appended then the corresponding max x (east) or
72 y (north) may be slightly adjusted to fit exactly the given
73 increment [by default the increment may be adjusted slightly to
74 fit the given domain]. Finally, instead of giving an increment
75 you may specify the number of nodes desired by appending +n to
76 the supplied integer argument; the increment is then recalcu‐
77 lated from the number of nodes and the domain. The resulting
78 increment value depends on whether you have selected a grid‐
79 line-registered or pixel-registered grid; see App-file-formats
80 for details. Note: if -Rgrdfile is used then the grid spacing
81 has already been initialized; use -I to override the values.
82 -Rwest/east/south/north[/zmin/zmax][+r][+uunit]
84 west, east, south, and north specify the region of interest, and
85 you may specify them in decimal degrees or in
86 [±]dd:mm[:ss.xxx][W|E|S|N] format Append +r if lower left and
87 upper right map coordinates are given instead of w/e/s/n. The
88 two shorthands -Rg and -Rd stand for global domain (0/360 and
89 -180/+180 in longitude respectively, with -90/+90 in latitude).
90 Alternatively for grid creation, give Rcodelon/lat/nx/ny, where
91 code is a 2-character combination of L, C, R (for left, center,
92 or right) and T, M, B for top, middle, or bottom. e.g., BL for
93 lower left. This indicates which point on a rectangular region
94 the lon/lat coordinate refers to, and the grid dimensions nx and
95 ny with grid spacings via -I is used to create the corresponding
96 region. Alternatively, specify the name of an existing grid
97 file and the -R settings (and grid spacing, if applicable) are
98 copied from the grid. Appending +uunit expects projected (Carte‐
99 sian) coordinates compatible with chosen -J and we inversely
100 project to determine actual rectangular geographic region. For
101 perspective view (-p), optionally append /zmin/zmax. In case of
102 perspective view (-p), a z-range (zmin, zmax) can be appended to
103 indicate the third dimension. This needs to be done only when
104 using the -Jz option, not when using only the -p option. In the
105 latter case a perspective view of the plane is plotted, with no
106 third dimension.
107
109 -Dfactor
110 Modify the sampling interval along flowlines. Default [0.5]
111 gives approximately 2 points within each grid box. Smaller fac‐
112 tors gives higher resolutions at the expense of longer process‐
113 ing time.
114 -Nupper_age
116 Set the upper age to assign seamounts whose crustal age is
117 unknown (i.e., NaN) [no upper age].
118 -S Normalize the resulting CVA grid to percentages of the CVA maxi‐
120 mum.
121 -T Truncate seamount ages exceeding the upper age set with -N [no
123 truncation].
124 -V[level] (more ...)
126 Select verbosity level [c].
127 -bi[ncols][t] (more ...)
129 Select native binary input. [Default is 5 input columns].
130 -dinodata (more ...)
132 Replace input columns that equal nodata with NaN.
133 -e[~]"pattern" | -e[~]/regexp/[i] (more ...)
135 Only accept data records that match the given pattern.
136 -V[level] (more ...)
138 Select verbosity level [c].
139 -icols[+l][+sscale][+ooffset][,...] (more ...)
141 Select input columns and transformations (0 is first column).
142 -ocols[,...] (more ...)
144 Select output columns (0 is first column).
145 -r (more ...)
147 Set pixel node registration [gridline].
148 -:[i|o] (more ...)
150 Swap 1st and 2nd column on input and/or output.
151 -^ or just -
153 Print a short message about the syntax of the command, then
154 exits (NOTE: on Windows just use -).
155 -+ or just +
157 Print an extensive usage (help) message, including the explana‐
158 tion of any module-specific option (but not the GMT common
159 options), then exits.
160 -? or no arguments
162 Print a complete usage (help) message, including the explanation
163 of all options, then exits.
164
166 All spherical rotations are applied to geocentric coordinates. This
167 means that incoming data points and grids are considered to represent
168 geodetic coordinates and must first be converted to geocentric coordi‐
169 nates. Rotations are then applied, and the final reconstructed points
170 are converted back to geodetic coordinates. This default behavior can
171 be bypassed if the ellipsoid setting PROJ_ELLIPSOID is changed to
172 Sphere.
173
175 To create a CVA image from the Pacific (x,y,z,r,t) data in the file
176 seamounts.d, using the DC85.d Euler poles, run
177 gmt hotspotter seamounts.d -EDC85.d -GCVA.nc -R130/260/-66/60 -I10m -N145 -T -V
179 This file can then be plotted with grdimage.
181
183 GMT distributes the EarthByte rotation model Global_Earth‐
184 Byte_230-0Ma_GK07_AREPS.rot. To use an alternate rotation file, create
185 an environmental parameters named GPLATES_ROTATIONS that points to an
186 alternate rotation file.
187
189 gmt, grdimage, grdrotater, grdspotter, project, mapproject, back‐
190 tracker, gmtpmodeler, grdpmodeler, grdrotater, originator
191
193 Wessel, P., 1999, "Hotspotting" tools released, EOS Trans. AGU, 80
194 (29), p. 319.
195 Wessel, P., 2008, Hotspotting: Principles and properties of a plate
197 tectonic Hough transform, Geochem. Geophys. Geosyst. 9(Q08004):
198 doi:10.1029/2008GC002058.
199
201 2019, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
2025.4.5 Feb 24, 2019 HOTSPOTTER(1)