Update:
Ok here is what I got....
Use the arrow keys to move around the map.
The reason why you can't reach the edge of the map is simple, you SHOULD NEVER REACH THE EDGE OF THE MAP! lol Maps should be created with a cushion of tiles so that the player will not be able to reach the maps edge or they will see that it cuts off and it will break the illusion of being a world instead of a flat image.
With this method of displaying tiles you could even have the tiles loop around so that when you reach the edge of the map you go back to the other side, so that it looks as if the map never ends, or that you are viewing a part of a world rather than a flat surface.
basically
going left:
if x > 0:
x = x + mapwidth
going right
if x > mapwidth:
x = x - mapwidth
Same thing with the height.
Although, this version moves the tiles themselves to new game coordinates and updates the tile. If more tiles were added to reach beyond the view then you could loop the array around and move the player to the new coordinate all the inner tiles would stay the same and only the outer tiles that are out of view would change.
UPDATE:
This map has 4,000,000 tiles. But only 121 actors. It displays an 11x11 clone array over the view to show that it doesn't have an map edges. Moving by the actor could be done using Move To() to create smoother moving and still no map edges and no lag and maps as large as you want.
Go ahead.. put the keydown on repeat... your computer won't lag and it will still take forever to reach the other side of the map.
Windowed or Fullscreen, FPS does not drop.
1 glitch, going diagonal with repeat on tears holes in the map. I am sure its because hes going to fast...
The Iso version uses a 35x35 actors = 1225 tile actors + 1 player actor. To display a 4 Million tile map.