gmtpmodeler(1)

1GMTPMODELER(1)                        GMT                       GMTPMODELER(1)
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NAME

6       gmtpmodeler - Evaluate a plate motion model at given locations
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SYNOPSIS

9       gmtpmodeler  table   -Erot_file -Sflags [  -Fpolygonfile ] [  -Tage ] [
10       -V[level] ] [ -bbinary ] [ -dnodata ] [ -eregexp  ]  [  -hheaders  ]  [
11       -iflags ] [ -oflags ] [ -:[i|o] ]
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13       Note:  No  space  is allowed between the option flag and the associated
14       arguments.
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DESCRIPTION

17       gmtpmodeler reads a table with lon, lat and optionally age triplets and
18       a  plate  motion  model and evaluates one of several model predictions.
19       Optionally, the user may supply a clipping polygon in  multiple-segment
20       format;  then,  only the part of the points inside the polygon are used
21       to determine the model prediction.  The results are written to standard
22       output.
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REQUIRED ARGUMENTS

25       table  Name  of one or more tables with geographical (lon, lat) coordi‐
26              nates and optionally a third column with ages  in  Myr.   If  no
27              file is given then we read from standard input.
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29       -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:
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34              lon lat tstart [tstop] angle [ khat a b c d e f g df ]
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36              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.  Alternatively, 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.
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54       -Sflags
55              Type  of  model  prediction(s). Append one or more items: choose
56              from a for plate motion azimuth,  d  for  great-circle  distance
57              between  current location and its origin at the ridge (in km), s
58              for plate motion model stage ID (1 is  youngest),  v  for  plate
59              motion  rate (in mm/yr), w for plate rotation rate (degree/Myr),
60              x for change in longitude relative to location of  crust  forma‐
61              tion,  y  for  change  in latitude relative to location of crust
62              formation, X for longitude of crust formation, and Y  for  lati‐
63              tude  of  crust formation.  If no arguments are given we default
64              to all [adsvwxyXY].
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OPTIONAL ARGUMENTS

67       -Fpolygonfile
68              Specify a multisegment closed polygon file  that  describes  the
69              area where the model should be evaluated; points outside will be
70              skipped [use all data points].
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72       -Tage  Use a fixed age for model evaluation (i.e.,  override  the  ages
73              given in the input table). This lets you evaluate the model at a
74              snapshot in time, and is a required option if  the  input  table
75              does not contain ages.
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77       -V[level] (more ...)
78              Select verbosity level [c].
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80       -bi[ncols][t] (more ...)
81              Select native binary input. [Default is 2 input columns].
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83       -d[i|o]nodata (more ...)
84              Replace  input  columns  that  equal  nodata with NaN and do the
85              reverse on output.
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87       -e[~]"pattern" | -e[~]/regexp/[i] (more ...)
88              Only accept data records that match the given pattern.
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90       -h[i|o][n][+c][+d][+rremark][+rtitle] (more ...)
91              Skip or produce header record(s).
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93       -icols[+l][+sscale][+ooffset][,...] (more ...)
94              Select input columns and transformations (0 is first column).
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96       -ocols[,...] (more ...)
97              Select output columns (0 is first column).
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99       -^ or just -
100              Print a short message about the  syntax  of  the  command,  then
101              exits (NOTE: on Windows just use -).
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103       -+ 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.
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108       -? or no arguments
109              Print a complete usage (help) message, including the explanation
110              of all options, then exits.
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GEODETIC VERSUS GEOCENTRIC COORDIINATES

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                                        ----
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EXAMPLES

127       We  will  use  a  table  with  locations  and  ages  of  Pacific  crust
128       (pac_age.txt),  a  plate motion model (Pac_APM.txt), and a polygon that
129       contains the outline of the present Pacific plate  (pac_clip_path.txt).
130       To  evaluate  the  plate  motion  azimuths  at the present time for the
131       Pacific, try
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133              gmt gmtpmodeler pac_age.txt -EPac_APM.txt -V -Fpac_clip_path.txt \
134                               -Sa -T0 > pac_dir_0.txt
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136       To determine the changes in latitude  since  crust  formation  for  the
137       entire Pacific, try
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139              gmt gmtpmodeler pac_age.txt -EPac_APM.txt -V -Fpac_clip_path.txt \
140                              -Sy > pac_dlat.txt
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142       To  determine  the  plate  motion velocities in effect when the Pacific
143       crust was formed, try
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145              gmt gmtpmodeler pac_age.txt -EPac_APM.txt -V -Fpac_clip_path.txt \
146                              -Sv > pac_vel.txt
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148       To determine how far the crust has moved since formation, try
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150              gmt gmtpmodeler pac_age.txt -EPac_APM.txt -V -Fpac_clip_path.txt \
151                              -Sd > pac_dist.txt
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153       To save the coordinates of the crust's formation, try
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155              gmt gmtpmodeler pac_age.txt -EPac_APM.txt -V -Fpac_clip_path.txt \
156                              -SXY > ac_origin_xy.txt
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NOTES

159       GMT   distributes   the   EarthByte   rotation   model    Global_Earth‐
160       Byte_230-0Ma_GK07_AREPS.rot.  To use an alternate rotation file, create
161       an environmental parameters named GPLATES_ROTATIONS that points  to  an
162       alternate rotation file.
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COPYRIGHT

169       2019, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
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1745.4.5                            Feb 24, 2019                   GMTPMODELER(1)