Insight

So there is nothing actually wrong with the code for moving the map around on screen.  The problem actually lies with the way that I have my player placed.  Currently the player is somewhere on the map grid, rather than somewhere on the displayed map.  The player moves around the displayed map with impunity, but when i need to update the underlying map shown, the player was getting screwed around.
Just need to rephrase the code to make the player move relative to the displayed map instead.  That will fix this little problem I think