The calculations were constrained; it was hoped to minimise the shifts from the coordinates based on the old triangulation. At eleven primary trig points from Dunnose on the Isle of Wight (456784 m E, 080150 m N) north to Great Whernside in Yorkshire (400202 E, 473904 N) the new latitudes and longitudes were adjusted to stay within a metre of the old ones. Once the new latitude and longitude of those eleven points were fixed the calculated location of every other point in the triangulation was based on them. By the time the retriangulation was completed, electronic distance measurement devices had come into use which could have greatly reduced the overall error.