No. There were far too many variables in play for the procedure to actually work. First of all, the staff and crystal medallion would have had to been at the correct height. Ancient peoples did not have precise measuring equipment, which is why a foot is the length of a foot and a cubit the length of a forearm. The length of Indy's staff would therefore not be the exact length needed. Secondly, the relationship between the sun and the horizon changes from day to day. Every day the sun rises further north or south from the previous day depending on the time of the year. If by chance he did have the staff at the correct height he would still have to hope it was the right time of the year. But there is one further problem: in the thousands of years since the map room was created the Earth has shifted on its axis (one of the reasons the Earth periodically has Ice Ages). Sailing ships in the past could often navigate at night because the Earth's axis pointed toward the North Star. At the time the map room was built the Earth's axis did not point at the North Star. Thus, there is no reason to think it would have worked. It's purely movie magic and myth and does make for one of the more memorable and exciting moments in the movie. Edit