While parallels determine the major climate zones (Tropics, Polar regions), meridians help geographers understand time zones and the relationship between distance and degrees. As you move toward the poles, the distance represented by one degree of longitude shrinks, which affects map projections and navigation calculations.
In geography, a is an imaginary half-circle running from the North Pole to the South Pole . It connects all places that share the same longitude . The word comes from Latin meridies meaning "midday" (all places on the same meridian experience solar noon at the same time). meridians geography