BACKTRACKER

No space between the option flag and the associated arguments. Use upper case for the option flags and lower case for modifiers.

−E

Give file with rotation poles and opening angles. This file must contain one record for each rotation; each record must be of the following format:

lon lat tstart [tstop] ccw-angle [k a b c d e f g]

−A

Used in conjunction with −Lb|f to limit the track output to those sections whose predicted ages fit between the young and old limits. If −LB|F is used instead then the limits apply to the stage ids. If no limits are supplied then individual limits for each seamount are expected in columns 4 and 5 of the input file.

−C

Expect Total Reconstruction Poles rather than Backward Stage Poles [Default]. File format is similar to the stage pole format except the youngest rotation must be listed first and that the tstart column is optional (assumed to be 0 Ma).

−D

Set the direction to go: −Df will go forward in time (from younger to older positions), while −Db will go backward in time (from older to younger positions) [Default].

−H

Input file(s) has Header record(s). Number of header records can be changed by editing your .gmtdefaults4 file. If used, GMT default is 1 header record. Use −Hi if only input data should have header records [Default will write out header records if the input data have them]. Blank lines and lines starting with # are always skipped.

−L

Specify a sampled path between initial and final position: −Lf will draw flowlines, while −Lb will draw backtrack (hotspot track) paths. Append sampling interval in km. If step < 0 then only the bend-times (knots) will be returned. When −LF or −LB is used, the third output column will contain the stage id (1 is youngest) [Default is along-track ages].

−M

Multiple segment file(s). Segments are separated by a special record. For ASCII files the first character must be flag [Default is ’>’]. For binary files all fields must be NaN and −b must set the number of output columns explicitly. By default the −M setting applies to both input and output. Use −Mi and −Mo to give separate settings.

−N

Set the maximum age to extend the oldest stage back in time [Default is no extension].

−Q

Assign a fixed age to all positions. Only lon, lat input is expected.

−S

When −L is set, the tracks are normally written to stdout as a multisegment file. Specify a filestem to have each track written to filestem.#, where # is the track number. The track number is also copied to the 4th output column.

−T

Set the current time [Default is 0 Ma].

−V

Selects verbose mode, which will send progress reports to stderr [Default runs "silently"].

−W

Rotates the given input (lon,lat,t) and calculates the confidence ellipse for the projected point. The input point must have a time coordinate that matches a particular finite rotation time, otherwise the point will be skipped. Append t or a to output time or angle, respectively, after the projected lon, lat. After these 2-3 items, we write azimuth, major, minor (in km) for the 95% confidence ellipse.

−:

Toggles between (longitude,latitude) and (latitude,longitude) input and/or output. [Default is (longitude,latitude)]. Append i to select input only or o to select output only. [Default affects both].

−bi

Selects binary input. Append s for single precision [Default is d (double)]. Uppercase S or D will force byte-swapping. Optionally, append ncol, the number of columns in your binary input file if it exceeds the columns needed by the program. Or append c if the input file is netCDF. Optionally, append var1/var2/... to specify the variables to be read. [Default is 3 input columns].

−bo

Selects binary output. Append s for single precision [Default is d (double)]. Uppercase S or D will force byte-swapping. Optionally, append ncol, the number of desired columns in your binary output file. [Default depends on settings].