[gmx-users] how to calculate the area of per lipid in membrane

[linfu]

Dear gmx community!

Could anyone help me how to perform the analysis of <the area of per lipid> 
after MEMBRANE simulation in NPT condition. because there is a protein inserted
in the membrane, it is difficult for me to calculate the area of per lipid directly.
what kinds of program can do such work.
Thank you very much in advance!

BEST REGARDS
Fu Lin