For an observer in the Northern Hemisphere, what geographical measurement is directly related to the altitude of Polaris above the northern horizon?

The observer's latitude

The altitude, or angle, of Polaris measured above the northern horizon provides an observer with a direct measure of their geographical latitude. If an observer is standing precisely at the North Pole, Polaris will appear directly overhead at an altitude of 90 degrees. Conversely, as an observer travels south towards the equator, Polaris sinks toward the horizon, reaching an altitude of 0 degrees exactly at the equator. South of the equator, Polaris drops completely out of view below the horizon. This constant relationship between the star's angular height and location makes it an indispensable navigational tool, as this angle remains fixed for a specific location throughout the night, unlike the apparent movement of the Sun or Moon.