my $seismic = Seismic->new( 'seismic.dat' );

for my $lineID ( keys %{ $seismic } ) {

    for my $stn ( values %{ $seismic->{ $lineID } } ) {

        $stn->[ Easting   ] -= $stn->[ Easting  ] * 0.00001;
        $stn->[ Northing  ] -= $stn->[ Northing ] * 0.000002;
        $stn->[ Elevation ] += 1;
        
        $stn->[ Other ] = int(
            ( $stn->[ Easting   ]
            * $stn->[ Northing  ]
            * $stn->[ Elevation ]
            ) / 3.0
        );
    }
}