possability of making a maphack

i was wondering if this was at all posable? u kno how in single player it saves the map u explore well i kno thers like 12 diff ones for like durance of hate but would it be at all possable to make a program that would be 100% clientside and just took the saved map that was allready explored and just loaded it and pasted it onto the screen? well i thought this was a good idea but some know it all will prob shoot it down but its worth a shot.