Line --+ | +-- Station | | | +---- Easting (x) | +---- Northing (y) | +---- Elevation (z) | +-- Length | +-- Group (Stn) Interval %Coord = ( $Line_1 => { stn_1 => coord_1, stn_2 => coord_2, stn_3 => coord_3, ... ... ... stn_n => coord_n, }, $Line_2 => { stn_1 => coord_1, stn_2 => coord_2, stn_3 => coord_3, ... ... ... stn_n => coord_n, }, # And so-on to $Line_n );