Data File

The data file contains five columns, distance from ridge (km), depth at that distance from the ridge (km)and the measured magnetic anomaly value (nT). (NOTE: it is assumed that the Earth's magnetic field, at the time when the measurement was done, has been subtracted from the recorded value so the anomaly value itself is only left. Magellan will do this for you in one of the future releases.) To use the data file filename when running Magellan it is specified after all the options (magellan [options] filename. Equivalently the data file can be specified in the configuration file, with the key data=filename. Here is an example of a data file, obtained from the Reykjanes Ridge (Hey et al., 2010)

% Everything written after the percentage sign is a comment
% This is a plain text file with the format below
% distance from ridge(km) depth(km) magnetic anomaly(nT)
-10.000000 0.76 14.91
-9.000000 0.831 358.37
-8.000000 0.744 1044.42
-7.000000 0.557 1745.77
-6.000000 0.528 1691.73
-5.000000 0.641 803.62
-4.000000 0.653 559.79
-3.000000 0.741 642.65
-2.000000 0.732 745.36
-1.000000 0.75 977.09
0.000000 0.86 639.72
1.000000 0.806 311.57
2.000000 0.703 496.94
3.000000 0.709 439.74
4.000000 0.723 351.59
5.000000 0.604 -19.61
6.000000 0.724 1066.69
7.000000 0.666 1695.18
8.000000 0.679 2128.43
9.000000 0.724 956.99
10.000000 0.722 494.87

The depth is always positive (due to the Cartesian coordinate system used, described in the section above). The distance between data points is up to the user and the resolution is never greater than the spacing of data points, i.e. if the spacing is 3 km then Magellan will arrange the magnetized blocks every 3 km so smaller reversal periods might not be detected (NOTE: This is a present defect in Magellan and will be fixed).