Hi Slobodan,

Point made, 1E-7, not 1E-6. Mia culpa. But it still works out that the resolution of the GPS system is limited to 9E-5 degrees. 90°/10E6 meters = 9E-6 degrees/meter, multiplied by 10 meters (precision of the system) = 9E-5°. If he is dealing with a system which incorporates land based beacons, he might have to worry about 1 cm relative precision, or 9E-8°. But if he is only dealing with the absolute precision of the GPS system, then there is no point in keeping more than 5 decimal places of a degree. So the question becomes, does one need double precision variables to maintain 5 decimal places? How about 8 decimal places?