bins for a nano droplet on a surface

Dear LAMMPS users,

I want to calculate the contact angle of this droplet on a surface :

Image result for water on graphene

I should divide this droplet to bins and get the number of atoms per bin .
How can i do that ?


I think you should put all those atoms in a group, then use compute chunk/atom and fix ave/chunk commands

Dear Alexey,

I am using these two command but I think i don’t know how i can use them !
for example bin/sphere or bin/3d give me sth like this :

Screenshot from 2018-07-29 17:11:41.jpg

this is the coord/density graph !
I can not understand what the problem is , the bin size is 2.5 !