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 stage poles and opening angles. This file must
30 contain one record for each stage; each record must be of the
31 following format:
32 lon lat tstart tstop ccw-angle
34 where tstart and tstop are in Ma and the rest is in degrees.
36 The oldest stage must be listed first. tstart (tstop) is the
37 age of the old (young) end of the stage. Blank lines and
38 records whose first column contains # will be ignored.
39 -G Specify name for output grid file.
41 -I x_inc [and optionally y_inc] is the grid spacing. Optionally,
43 append a suffix modifier. Geographical (degrees) coordinates:
44 Append m to indicate arc minutes or c to indicate arc seconds.
45 If one of the units e, k, i, or n is appended instead, the
46 increment is assumed to be given in meter, km, miles, or nauti‐
47 cal miles, respectively, and will be converted to the equivalent
48 degrees longitude at the middle latitude of the region (the con‐
49 version depends on ELLIPSOID). If /y_inc is given but set to 0
50 it will be reset equal to x_inc; otherwise it will be converted
51 to degrees latitude. All coordinates: If = is appended then the
52 corresponding max x (east) or y (north) may be slightly adjusted
53 to fit exactly the given increment [by default the increment may
54 be adjusted slightly to fit the given domain]. Finally, instead
55 of giving an increment you may specify the number of nodes
56 desired by appending + to the supplied integer argument; the
57 increment is then recalculated from the number of nodes and the
58 domain. The resulting increment value depends on whether you
59 have selected a gridline-registered or pixel-registered grid;
60 see Appendix B for details.
61 -R west, east, south, and north specify the Region of interest, and
63 you may specify them in decimal degrees or in
64 [+-]dd:mm[:ss.xxx][W|E|S|N] format. Append r if lower left and
65 upper right map coordinates are given instead of w/e/s/n. The
66 two shorthands -Rg and -Rd stand for global domain (0/360 and
67 -180/+180 in longitude respectively, with -90/+90 in latitude).
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70 -C Expect Total Reconstruction Poles rather than Backward Stage
71 Poles [Default]. File format is similar to the stage pole for‐
72 mat except the youngest rotation must be listed first and that
73 the tstart column is optional (assumed to be 0 Ma).
74 -D Modify the sampling interval along flowlines. Default [0.5]
76 gives approximately 2 points within each grid box. Smaller fac‐
77 tors gives higher resolutions at the expense of longer process‐
78 ing time.
79 -F Force pixel registration [Default is grid registration].
81 -H Input file(s) has Header record(s). Number of header records
83 can be changed by editing your .gmtdefaults4 file. If used, GMT
84 default is 1 header record. Use -Hi if only input data should
85 have header records [Default will write out header records if
86 the input data have them]. Blank lines and lines starting with #
87 are always skipped.
88 -N Set the upper age to assign seamounts whose crustal age is
90 unknown (i.e. NaN) [no upper age].
91 -S Normalize the resulting CVA grid to percentages of the CVA maxi‐
93 mum.
94 -T Truncate seamount ages exceeding the upper age set with -N [no
96 truncation].
97 -V Selects verbose mode, which will send progress reports to stderr
99 [Default runs "silently"].
100 -: Toggles between (longitude,latitude) and (latitude,longitude)
102 input and/or output. [Default is (longitude,latitude)]. Append
103 i to select input only or o to select output only. [Default
104 affects both].
105 -bi Selects binary input. Append s for single precision [Default is
107 d (double)]. Uppercase S or D will force byte-swapping.
108 Optionally, append ncol, the number of columns in your binary
109 input file if it exceeds the columns needed by the program. Or
110 append c if the input file is netCDF. Optionally, append
111 var1/var2/... to specify the variables to be read. [Default is
112 5 input columns].
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115 To create a CVA image from the Pacific (x,y,z,r,t) data in the file
116 seamounts.d, using the DC85.d Euler poles, run
117 hotspotter seamounts.d -EDC85.d -GCVA.grd -R130/260/-66/60 -I10m -N145
119 -T -V
120 This file can then be plotted with grdimage.
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124 GMT(1), grdimage(1), project(1), mapproject(1), backtracker(1), origi‐
125 nator(1)
126
128 Wessel, P., 1999, "Hotspotting" tools released, EOS Trans. AGU, 80
129 (29), p. 319.
130GMT 4.3.1 15 May 2008 HOTSPOTTER(1)