Dear APBS users,

I have successfully calculated the electrostatic potential for my protein and I have written the density map in the file pot.dx. I am able to visualize the content of the pot.dx file using VMD or pymol.
I am interested in understanding how far the electrostatic potential reachs out from the protein surface to the solvent in terms of Angstroms or A^2 or A^3. There is any way (any software) to compute it?

Thank you in advance for any helps.