Geographic

set xtics geographic indicates that x-axis values are to be interpreted as a geographic coordinate measured in degrees. Use set xtics format or set format x to specify the appearance of the axis tick labels. The format specifiers for geographic data are as follows:

      %D                   = integer degrees
      %<width.precision>d  = floating point degrees
      %M                   = integer minutes
      %<width.precision>m  = floating point minutes
      %S                   = integer seconds
      %<width.precision>s  = floating point seconds
      %E                   = label with E/W instead of +/-
      %N                   = label with N/S instead of +/-

For example, the command set format x "%Ddeg %5.2mmin %E" will cause x coordinate -1.51 to be labeled as " 1deg 30.60min W".

If the xtics are left in the default state (set xtics numeric) the coordinate will be reported as a decimal number of degrees, and format will be assumed to contain normal numeric format specifiers rather than the special set above.