The international date line is defined as an imaginary line that goes north and south through the Pacific Ocean.

The Tropic of Capricorn (or the Southern Tropic) is the circle of latitude that contains the subsolar point on the December (or southern) solstice

The Tropic of Cancer, also referred to as the Northern Tropic, is the most northerly circle of latitude on the Earth
a diagrammatic representation of an area of land or sea showing physical features, cities, roads, etc.

a spherical or rounded object.