ph_seg =
0 2.100000000000000
2.100000000000000 2.130000000000000
2.130000000000000 2.210000000000000
2.210000000000000 2.320000000000000
2.320000000000000 2.420000000000000
2.420000000000000 2.470000000000000
2.470000000000000 2.560000000000000
2.560000000000000 2.640000000000000
2.640000000000000 2.720000000000000
2.720000000000000 2.800000000000000
2.800000000000000 2.830000000000000
2.830000000000000 2.880000000000000
2.880000000000000 2.940000000000000
2.940000000000000 2.980000000000000
2.980000000000000 3.010000000000000
3.010000000000000 3.110000000000000
3.110000000000000 3.210000000000000
3.210000000000000 3.270000000000000
3.270000000000000 3.420000000000000
3.420000000000000 3.940000000000000
3.940000000000000 3.990000000000000
3.990000000000000 4.930000000000000