1GRDROTATER(1) GMT GRDROTATER(1)
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6 grdrotater - Finite rotation reconstruction of geographic grid
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9 grdrotater ingrdfile -Erot_file|lon/lat/angle
10 -Goutgrdfile [ -Drotoutline ] [ -Fpolygonfile ] [ -N ] [ -Rregion
11 ] [ -S ] [ -Tages ] [ -V[level] ] [ -bbinary ] [ -dnodata ] [
12 -hheaders ] [ -nflags ] [ -:[i|o] ]
13 Note: No space is allowed between the option flag and the associated
15 arguments.
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18 grdrotater reads a geographical grid and reconstructs it given total
19 reconstruction rotations. Optionally, the user may supply a clipping
20 polygon in multiple-segment format; then, only the part of the grid
21 inside the polygon is used to determine the reconstructed region. The
22 outlines of the reconstructed region is also returned provided the
23 rotated region is not the entire globe.
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26 ingrdfile
27 Name of a grid file in geographical (lon, lat) coordinates.
28 -Erotfile
30 Give file with rotation parameters. This file must contain one
31 record for each rotation; each record must be of the following
32 format:
33 lon lat tstart [tstop] angle [ khat a b c d e f g df ]
35 where tstart and tstop are in Myr and lon lat angle are in
37 degrees. tstart and tstop are the ages of the old and young ends
38 of a stage. If tstop is not present in the record then a total
39 reconstruction rotation is expected and tstop is implicitly set
40 to 0 and should not be specified for any of the records in the
41 file. If a covariance matrix C for the rotation is available it
42 must be specified in a format using the nine optional terms
43 listed in brackets. Here, C = (g/khat)*[ a b d; b c e; d e f ]
44 which shows C made up of three row vectors. If the degrees of
45 freedom (df) in fitting the rotation is 0 or not given it is set
46 to 10000. Blank lines and records whose first column contains #
47 will be ignored. You may prepend a leading + to the filename to
48 indicate you wish to invert the rotations. Alternative 1: Give
49 the filename composed of two plate IDs separated by a hyphen
50 (e.g., PAC-MBL) and we will instead extract that rotation from
51 the GPlates rotation database. We return an error if the rota‐
52 tion cannot be found. Alternative 2: Specify lon/lat/angle,
53 i.e., the longitude, latitude, and opening angle (all in degrees
54 and separated by /) for a single total reconstruction rotation.
55 -Goutgrdfile
57 Name of output grid. This is the grid with the data recon‐
58 structed according to the specified rotation. If more than one
59 reconstruction time is implied then outgrdfile must contain a
60 C-format specifier to format a floating point number (recon‐
61 struction time) to text.
62
64 -Drotoutline
65 Name of the grid polygon outline file. This represents the out‐
66 line of the grid reconstructed to the specified time. If more
67 than one reconstruction time is implied then rotoutline must
68 contain a C-format specifier to format a floating point number
69 (reconstruction time) to text. If only one time is implied and
70 -D is not set then we write the polygon to stdout (but see -N).
71 -Fpolygonfile
73 Specify a multisegment closed polygon file that describes the
74 inside area of the grid that should be projected [Default
75 projects entire grid].
76 -N Do Not output the rotated polygon outline [Default will write it
78 to stdout, or to a file via -D].
79 -Rwest/east/south/north[/zmin/zmax][+r][+uunit]
81 west, east, south, and north specify the region of interest, and
82 you may specify them in decimal degrees or in
83 [±]dd:mm[:ss.xxx][W|E|S|N] format Append +r if lower left and
84 upper right map coordinates are given instead of w/e/s/n. The
85 two shorthands -Rg and -Rd stand for global domain (0/360 and
86 -180/+180 in longitude respectively, with -90/+90 in latitude).
87 Alternatively for grid creation, give Rcodelon/lat/nx/ny, where
88 code is a 2-character combination of L, C, R (for left, center,
89 or right) and T, M, B for top, middle, or bottom. e.g., BL for
90 lower left. This indicates which point on a rectangular region
91 the lon/lat coordinate refers to, and the grid dimensions nx and
92 ny with grid spacings via -I is used to create the corresponding
93 region. Alternatively, specify the name of an existing grid
94 file and the -R settings (and grid spacing, if applicable) are
95 copied from the grid. Appending +uunit expects projected (Carte‐
96 sian) coordinates compatible with chosen -J and we inversely
97 project to determine actual rectangular geographic region. For
98 perspective view (-p), optionally append /zmin/zmax. In case of
99 perspective view (-p), a z-range (zmin, zmax) can be appended to
100 indicate the third dimension. This needs to be done only when
101 using the -Jz option, not when using only the -p option. In the
102 latter case a perspective view of the plane is plotted, with no
103 third dimension.
104 -S Skip the rotation of the grid, just rotate the polygon outline
106 (requires -F if no grid is provided).
107 -Tages Sets the desired reconstruction times. For a single time append
109 the desired time. For an equidistant range of reconstruction
110 times give -Tstart/stop/inc or -Tstart/stop/npoints+. For an
111 non-equidistant set of reconstruction times please pass them via
112 the first column in a file, e.g., -Tagefile. If no -T option is
113 given and -E specified a rotation file then we equate the rota‐
114 tion file times with the reconstruction times.
115 -V[level] (more ...)
117 Select verbosity level [c].
118 -bi[ncols][t] (more ...)
120 Select native binary input. [Default is 2 input columns].
121 -bo[ncols][type] (more ...)
123 Select native binary output. [Default is same as input].
124 -d[i|o]nodata (more ...)
126 Replace input columns that equal nodata with NaN and do the
127 reverse on output.
128 -h[i|o][n][+c][+d][+rremark][+rtitle] (more ...)
130 Skip or produce header record(s).
131 -:[i|o] (more ...)
133 Swap 1st and 2nd column on input and/or output.
134 -n[b|c|l|n][+a][+bBC][+c][+tthreshold] (more ...)
136 Select interpolation mode for grids.
137 -^ or just -
139 Print a short message about the syntax of the command, then
140 exits (NOTE: on Windows just use -).
141 -+ or just +
143 Print an extensive usage (help) message, including the explana‐
144 tion of any module-specific option (but not the GMT common
145 options), then exits.
146 -? or no arguments
148 Print a complete usage (help) message, including the explanation
149 of all options, then exits.
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152 Resample or sampling of grids will use various algorithms (see -n) that
153 may lead to possible distortions or unexpected results in the resampled
154 values. One expected effect of resampling with splines is the tendency
155 for the new resampled values to slightly exceed the global min/max lim‐
156 its of the original grid. If this is unacceptable, you can impose
157 clipping of the resampled values values so they do not exceed the input
158 min/max values by adding +c to your -n option.
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161 All spherical rotations are applied to geocentric coordinates. This
162 means that incoming data points and grids are considered to represent
163 geodetic coordinates and must first be converted to geocentric coordi‐
164 nates. Rotations are then applied, and the final reconstructed points
165 are converted back to geodetic coordinates. This default behavior can
166 be bypassed if the ellipsoid setting PROJ_ELLIPSOID is changed to
167 Sphere.
168
170 To rotate the data defined by grid topo.nc and the polygon outline
171 clip_path.d, using a total reconstruction rotation with pole at (135.5,
172 -33.0) and a rotation angle of 37.3 degrees and bicubic interpolation,
173 try
174 gmt grdrotater topo.nc -E135.5/-33/37.3 -V -Fclip_path.d -Grot_topo.nc > rot_clip_path.d
176 To rotate the entire grid faa.nc back to 32 Ma using the rotation file
178 rotations.txt and a bilinear interpolation, try
179 gmt grdrotater faa.nc -Erotations.txt -T32 -V -Grot_faa.nc -nl > rot_faa_path.d
181 To just see how the outline of the grid large.nc will plot after the
183 same rotation, try
184 gmt grdrotater large.nc -Erotations.txt -T32 -V -S \| psxy -Rg -JH180/6i -B30 -W0.5p \| gv -
186 To rotate the grid topo.nc back to 100 Ma using the rotation file rota‐
188 tions.txt and request a reconstruction every 10 Myr, saving both grids
189 and outlines to filenames that derive from templates, try
190 gmt grdrotater topo.nc -Erotations.txt -T10/100/10 -V -Grot_topo_%g.nc -Drot_topo_path_%g.d
192 Let say you have rotated gridA.nc and gridB.nc, restricting each rota‐
194 tion to nodes inside polygons polyA.d and polyB.d, respectively, using
195 rotation A = (123W,22S,16,4) and rotation B = (108W, 16S, -14.5),
196 yielding rotated grids rot_gridA.nc and rot_gridB.nc. To determine the
197 region of overlap between the rotated grids, we use grdmath:
198 gmt grdmath 1 rot_gridA.nc ISNAN SUB 1 rot_gridB.nc ISNAN SUB 2 EQ = overlap.nc
200 The grid overlap.nc now has 1s in the regions of overlap and 0 else‐
202 where. You can use it as a mask or use grdcontour -D to extract a poly‐
203 gon (i.e., a contour).
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206 GMT distributes the EarthByte rotation model Global_Earth‐
207 Byte_230-0Ma_GK07_AREPS.rot. To use an alternate rotation file, create
208 an environmental parameters named GPLATES_ROTATIONS that points to an
209 alternate rotation file.
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212 backtracker, grdcontour, gmtpmodeler, grdmath, grdpmodeler, grdspotter,
213 hotspotter, originator, rotconverter
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216 2019, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
2175.4.5 Feb 24, 2019 GRDROTATER(1)