What is the third type of north listed?

The third type of north referred to in navigation and map-making is Magnetic North. This concept is crucial for understanding how to orient a compass and how the Earth's magnetic field affects navigation.

Magnetic North is defined as the direction that a compass needle points, which is toward the Earth's magnetic north pole. This differs from True North, which points directly to the North Pole irrespective of local magnetic variations, and Grid North, which is determined by the grid lines on a map.

The significance of understanding Magnetic North lies in the fact that compasses are integral to navigation, especially when determining one's location and direction in outdoor activities or military operations. Each one of these types of north serves its purpose and is relevant to specific contexts of navigation, but Magnetic North is particularly important when using a compass to find direction in the field.

In contrast, the other terms represent different aspects of navigation: True North is the fixed point of reference for accurately determining geographical direction, and Grid North refers to the orientation used in mapping based on a grid system. Derived North is less commonly used and generally pertains to calculations or interpretations of north based on different reference systems rather than being a direct method of orientation. Understanding all these distinctions is key for effective navigation and map reading.