The eye is continuously bathed in a fluid secreted by the lacrimal gland which flows

Inside the eye?
don't think I'm right but i hope it helps!

He should put sand around the spill in order to contain it so that it won't spread

Are you asking about a street map usage  if so here is your answer  a street map for a very limited area could simply be a bit map or a .jpg image.  but a more general map would probably store the streets as vectors.  but you shouldn't assume that there is one way to do it