B.1.1.1 Optional file header records

The first data record may be preceded by 1 or more header records. When using such files, make sure to use the -H option and set the parameter N_HEADER_RECS in the .gmtdefaults4 file (System default is 1 header record if -H is set; you may also use -Hnrecs directly). Fields within a record must be separated by spaces, tabs, or commas. Each field can be an integer or floating-point number or a geographic coordinate string using the [+$\vert$-]dd[:mm[:ss]][W$\vert$S$\vert$N$\vert$E$\vert$w$\vert$s$\vert$n$\vert$e] format. Thus, 12:30:44.5W, 17.5S, 1:00:05, and 200:45E are all valid input strings.