I cannot tell you how many odd behaviors will creep into your code if you are assuming your maps are a 20 by 20 grid, and an error in your “print maps to screen” methodology makes it a 21 column map instead.  Especially if your tiles all default to the same texture that is literally designed to bleed together into a mess with divide.  An uncountable mess.  I changed it to a texture with borders around each tile, and I think I actually like it better this way.  I must have wasted at least two hours because of this today.  Time is drawing around my neck like a noose it seems, and yet I almost have my level editor done.  My tile editor is ready, sans tiles.  Now I just need to be able to draw paths for the enemy AI, and to actually place the enemy guards in my level.  Easy enough, right?  Right?