public void setTroup(Troop newTroup){
		//we remove the territory to the old owner if the troups is not its
		if(troop!=null && (newTroup==null || newTroup.getFamily()!=troop.getFamily())){
			troop.getFamily().removeTerritory(this);
		}
		this.troop=newTroup;
		if(newTroup!=null){
			owner=newTroup.getFamily();
			owner.addTerritory(this);
			// if this is a land with a port we change the owner of the troops in the port 
			if(this instanceof Land && this.havePort()){
				this.getPort().changeOwner(newTroup.getFamily());
			}
		}else{owner=null;} // verifier que ça ne pose pas de problemes
	}