Before revision: Notation Heading is typically based on compass directions, so 0° (or 360°) indicates a direction toward true North , 90° indicates a direction toward true East , 180° is true South , and 270° is true West .
After revision: Notation Heading is typically based on cardinal directions, so 0° (or 360°) indicates a direction toward true north , 90° true east , 180° true south , and 270° true west .