'Open' in the Bible

How is the land in which they live, is it good or bad? And how are the cities in which they live, are they like open camps or with fortifications?

As he finished speaking all these words, the ground that was under them split open;

Every open vessel, which has no covering tied down on it, shall be unclean.

Also, anyone who in the open field touches one who has been slain with a sword or who has died naturally, or a human bone or a grave, shall be unclean for seven days.