1HOTSPOTTER(1) Generic Mapping Tools HOTSPOTTER(1)
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6 hotspotter - Create CVA image from seamount flowlines
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9 hotspotter [infile(s)] -Estage_file -GCVAgrid
10 -Ixinc[unit][=|+][/yinc[unit][=|+]] -Rwest/east/south/north[r] [ -C ] [
11 -Dfactor ] [ -F ] [ -H[i][nrec] ] [ -Nupper_age ] [ -S ] [ -T ] [ -V ]
12 [ -:[i|o] ] [ -bi[s|S|d|D[ncol]|c[var1/...]] ]
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15 hotspotter reads (longitude, latitude, amplitude, radius, age) records
16 from infiles [or standard input] and calculates flowlines using the
17 specified stage pole (Euler) rotations. These flowlines are convolved
18 with the shape of the seamount (using a Gaussian shape given amplitude
19 and radius = 6 sigma) and added up to give a Cumulative Volcano Ampli‐
20 tude grid (CVA). See option -: on how to read (latitude,longitude,...)
21 files.
22 No space between the option flag and the associated arguments.
23 Use upper case for the option flags and lower case for modifiers.
24 infile(s)
26 Data file(s) to be processed. If not given, standard input is
27 read.
28 -E Give file with rotation parameters. This file must contain one
30 record for each rotation; each record must be of the following
31 format:
32 lon lat tstart [tstop] angle [ khat a b c d e f g df ]
34 where tstart and tstop are in Myr and lon lat angle are in
36 degrees. tstart and tstop are the ages of the old and young
37 ends of a stage. If -C is set then a total reconstruction rota‐
38 tion is expected and tstop is implicitly set to 0 and should not
39 be specified in the file. If a covariance matrix C for the
40 rotation is available it must be specified in a format using the
41 nine optional terms listed in brackets. Here, C = (g/khat)*[ a
42 b d; b c e; d e f ] which shows C made up of three row vectors.
43 If the degrees of freedom (df) in fitting the rotation is 0 or
44 not given it is set to 10000. Blank lines and records whose
45 first column contains # will be ignored.
46 -G Specify name for output grid file.
48 -I x_inc [and optionally y_inc] is the grid spacing. Optionally,
50 append a suffix modifier. Geographical (degrees) coordinates:
51 Append m to indicate arc minutes or c to indicate arc seconds.
52 If one of the units e, k, i, or n is appended instead, the
53 increment is assumed to be given in meter, km, miles, or nauti‐
54 cal miles, respectively, and will be converted to the equivalent
55 degrees longitude at the middle latitude of the region (the con‐
56 version depends on ELLIPSOID). If /y_inc is given but set to 0
57 it will be reset equal to x_inc; otherwise it will be converted
58 to degrees latitude. All coordinates: If = is appended then the
59 corresponding max x (east) or y (north) may be slightly adjusted
60 to fit exactly the given increment [by default the increment may
61 be adjusted slightly to fit the given domain]. Finally, instead
62 of giving an increment you may specify the number of nodes
63 desired by appending + to the supplied integer argument; the
64 increment is then recalculated from the number of nodes and the
65 domain. The resulting increment value depends on whether you
66 have selected a gridline-registered or pixel-registered grid;
67 see Appendix B for details. Note: if -Rgrdfile is used then
68 grid spacing has already been initialized; use -I to override
69 the values.
70 -R west, east, south, and north specify the Region of interest, and
72 you may specify them in decimal degrees or in
73 [+-]dd:mm[:ss.xxx][W|E|S|N] format. Append r if lower left and
74 upper right map coordinates are given instead of w/e/s/n. The
75 two shorthands -Rg and -Rd stand for global domain (0/360 and
76 -180/+180 in longitude respectively, with -90/+90 in latitude).
77 Alternatively, specify the name of an existing grid file and the
78 -R settings (and grid spacing, if applicable) are copied from
79 the grid.
80
82 -C Expect Total Reconstruction Rotations rather than Forward Stage
83 Rotations [Default]. File format is similar to the stage pole
84 format except that the tstart column is not present (assumed to
85 be 0 Ma).
86 -D Modify the sampling interval along flowlines. Default [0.5]
88 gives approximately 2 points within each grid box. Smaller fac‐
89 tors gives higher resolutions at the expense of longer process‐
90 ing time.
91 -F Force pixel registration [Default is grid registration].
93 -H Input file(s) has header record(s). If used, the default number
95 of header records is N_HEADER_RECS. Use -Hi if only input data
96 should have header records [Default will write out header
97 records if the input data have them]. Blank lines and lines
98 starting with # are always skipped.
99 -N Set the upper age to assign seamounts whose crustal age is
101 unknown (i.e. NaN) [no upper age].
102 -S Normalize the resulting CVA grid to percentages of the CVA maxi‐
104 mum.
105 -T Truncate seamount ages exceeding the upper age set with -N [no
107 truncation].
108 -V Selects verbose mode, which will send progress reports to stderr
110 [Default runs "silently"].
111 -: Toggles between (longitude,latitude) and (latitude,longitude)
113 input and/or output. [Default is (longitude,latitude)]. Append
114 i to select input only or o to select output only. [Default
115 affects both].
116 -bi Selects binary input. Append s for single precision [Default is
118 d (double)]. Uppercase S or D will force byte-swapping.
119 Optionally, append ncol, the number of columns in your binary
120 input file if it exceeds the columns needed by the program. Or
121 append c if the input file is netCDF. Optionally, append
122 var1/var2/... to specify the variables to be read. [Default is
123 5 input columns].
124
126 To create a CVA image from the Pacific (x,y,z,r,t) data in the file
127 seamounts.d, using the DC85.d Euler poles, run
128 hotspotter seamounts.d -EDC85.d -GCVA.grd -R130/260/-66/60 -I10m -N145
130 -T -V
131 This file can then be plotted with grdimage.
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135 Data coordinates are assumed to be geodetic and will automatically be
136 converted to geocentric before spherical rotations are performed. We
137 convert back to geodetic coordinates for output. Note: If your data
138 already are geocentric, you can avoid the conversion by using --ELLIP‐
139 SOID=sphere.
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142 GMT(1), grdimage(1), grdrotater(1), grdspotter(1), project(1), mappro‐
143 ject(1), backtracker(1), originator(1)
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146 Wessel, P., 1999, "Hotspotting" tools released, EOS Trans. AGU, 80
147 (29), p. 319.
148GMT 4.5.6 10 Mar 2011 HOTSPOTTER(1)