Positions are traditionally given using degrees, minutes, and seconds of arcs for latitude, the arc north or south of the equator, and for longitude, the arc east or west of the Prime Meridian. Any position on or above the Earth's reference ellipsoid can be precisely given with this method. However, because of the somewhat clumsy base-60 nature of minutes and seconds, positions are frequently expressed in fractional degrees only, expressed in decimal form to an equal amount of precision.