1GRDPMODELER(1) GMT GRDPMODELER(1)
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6 grdpmodeler - Evaluate a plate motion model on a geographic grid
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9 grdpmodeler agegrdfile -Erot_file -Sflags [ -Fpolygonfile ] [ -Gout‐
10 grdfile ] [ -Tage ] [ -V[level] ] [ -bbinary ] [ -dnodata ] [ -hhead‐
11 ers ] [ -:[i|o] ]
12 Note: No space is allowed between the option flag and the associated
14 arguments.
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17 grdpmodeler reads a geographical age grid and a plate motion model and
18 evaluates one of several model predictions. Optionally, the user may
19 supply a clipping polygon in multiple-segment format; then, only the
20 part of the grid inside the polygon is used to determine the model pre‐
21 diction; the remainder of the grid is set to NaN.
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24 ingrdfile
25 Name of a grid file in geographical (lon, lat) coordinates with
26 ages in Myr.
27 -Erotfile
29 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 ends
37 of a stage. If tstop is not present in the record then a total
38 reconstruction rotation is expected and tstop is implicitly set
39 to 0 and should not be specified for any of the records in the
40 file. If a covariance matrix C for the rotation is available it
41 must be specified in a format using the nine optional terms
42 listed in brackets. Here, C = (g/khat)*[ a b d; b c e; d e f ]
43 which shows C made up of three row vectors. If the degrees of
44 freedom (df) in fitting the rotation is 0 or not given it is set
45 to 10000. Blank lines and records whose first column contains #
46 will be ignored. You may prepend a leading + to the filename to
47 indicate you wish to invert the rotations. Alternatively, give
48 the filename composed of two plate IDs separated by a hyphen
49 (e.g., PAC-MBL) and we will instead extract that rotation from
50 the GPlates rotation database. We return an error if the rota‐
51 tion cannot be found.
52 -Sflags
54 Type of model prediction(s). Append one or more items: choose
55 from a for plate motion azimuth, d for great-circle distance
56 between current location and its origin at the ridge (in km), s
57 for plate motion model stage ID (1 is youngest), v for plate
58 motion rate (in mm/yr), w for plate rotation rate (degree/Myr),
59 x for change in longitude relative to location of crust forma‐
60 tion, y for change in latitude relative to location of crust
61 formation, X for longitude of crust formation, and Y for lati‐
62 tude of crust formation. If no arguments are given we default
63 to all [adsvwxyXY].
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66 -Fpolygonfile
67 Specify a multisegment closed polygon file that describes the
68 inside area of the grid where the model should be evaluated; the
69 outside will be set to NaN [Default evaluates model on the
70 entire grid].
71 -Goutgrdfile
73 Name of output grid. This is the grid with the model predictions
74 given the specified rotations. Note: If you specified more than
75 one model prediction in -S then the filename must be a template
76 that contains the format %s; this will be replaced with the cor‐
77 responding tags az, dist, stage, vel, omega, dlon, dlat, lon,
78 lat. If the -G option is not used then we create no grids and
79 instead write lon, lat, age, predictions records to standard
80 output.
81 -Tage Use a fixed age for model evaluation (i.e., override the ages in
83 the age grid). This lets you evaluate the model at a snapshot in
84 time.
85 -V[level] (more ...)
87 Select verbosity level [c].
88 -bi[ncols][t] (more ...)
90 Select native binary input. [Default is 2 input columns].
91 -d[i|o]nodata (more ...)
93 Replace input columns that equal nodata with NaN and do the
94 reverse on output.
95 -h[i|o][n][+c][+d][+rremark][+rtitle] (more ...)
97 Skip or produce header record(s).
98 -^ or just -
100 Print a short message about the syntax of the command, then
101 exits (NOTE: on Windows just use -).
102 -+ or just +
104 Print an extensive usage (help) message, including the explana‐
105 tion of any module-specific option (but not the GMT common
106 options), then exits.
107 -? or no arguments
109 Print a complete usage (help) message, including the explanation
110 of all options, then exits.
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113 All spherical rotations are applied to geocentric coordinates. This
114 means that incoming data points and grids are considered to represent
115 geodetic coordinates and must first be converted to geocentric coordi‐
116 nates. Rotations are then applied, and the final reconstructed points
117 are converted back to geodetic coordinates. This default behavior can
118 be bypassed if the ellipsoid setting PROJ_ELLIPSOID is changed to
119 Sphere.
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122 We will use a grid with Pacific crust ages (pac_age.nc), a plate motion
123 model (Pac_APM.d), and a polygon that contains the outline of the
124 present Pacific plate (pac_clip_path.d). To evaluate the plate motion
125 azimuths at the present time for the Pacific, try
126 gmt grdpmodeler pac_age.nc -EPac_APM.d -V -Fpac_clip_path.d \
128 -Gpac_dir_0.nc -Sa -T0
129 To determine the changes in latitude since crust formation for the
131 entire Pacific, try
132 gmt grdpmodeler pac_age.nc -EPac_APM.d -V -Fpac_clip_path.d \
134 -Gpac_dlat.nc -Sy
135 To determine the plate motion velocities in effect when the Pacific
137 crust was formed, try
138 gmt grdpmodeler pac_age.nc -EPac_APM.d -V -Fpac_clip_path.d \
140 -Gpac_vel.nc -Sv
141 To determine how far the crust has moved since formation, try
143 gmt grdpmodeler pac_age.nc -EPac_APM.d -V -Fpac_clip_path.d \
145 -Gpac_dist.nc -Sd
146 To save the coordinates of the crust's formation to separate grids, try
148 gmt grdpmodeler pac_age.nc -EPac_APM.d -V -Fpac_clip_path.d \
150 -Gpac_origin_%s.nc -SXY
151 To repeat the same exercise but save output lon,lat,age,xorigin,yorigin
153 to a table, use
154 gmt grdpmodeler pac_age.nc -EPac_APM.d -V -Fpac_clip_path.d -SXY > origin.txt
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158 GMT distributes the EarthByte rotation model Global_Earth‐
159 Byte_230-0Ma_GK07_AREPS.rot. To use an alternate rotation file, create
160 an environmental parameters named GPLATES_ROTATIONS that points to an
161 alternate rotation file.
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164 backtracker, gmtpmodeler, grdrotater, grdspotter, hotspotter, origina‐
165 tor, rotconverter
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168 2019, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
1695.4.5 Feb 24, 2019 GRDPMODELER(1)