Thanks for the reply I will remember to add more information next time.
For anyone interested: In North America for process piping, the first letter is the direction from the "bench mark" (reference point) on the drawing, i.e. N would be North, S would be South, etc. The first digit after the letter is the number of hundreds of feet from the bench mark, i.e. 1 is 100', 2 is 200', etc. So N1+70' - 6" would be 170 feet 6 inches North of the bench mark on the drawing.