G_mindist algorithm

GROMACS version: 2021.1
GROMACS modification: No

I’m using g_mindist -on to calculate the number of water oxygens that are within a certain distance from the atoms of a ligand. Is the value outputted in numcont.xvg the number of water oxygens within the specified distance as computed from the atomic surfaces or the atomic centers of the ligand atoms?

From the atomic centers. You may be able to use the -d option to calculate how many are in contact (with the contact distance specified by you).

Thank you