cartography Cartography (; from , 'papyrus, sheet of paper, map'; and , 'write') is the study and practice of making and using maps. Combining science, aesthetics and technique, cartography builds on the premise that reality (or an imagined reality) can ...

, a phase line is a line to show most often changing phases of a military operation,

Military usage

The term is also used in

military terminology Military terminology refers to the terminology, terms and language of military organizations, military personnel, personnel, and military doctrine. Much like other forms of corporate jargon, military terminology is distinguishable from colloquia ...

to refer to an imaginary line on a map used to coordinate phases of operations. They are usually distinguished with different code names, varying by the particulars of the mission such as location and nature. By the same token, phase lines are frequently used after a battle or a

military campaign A military campaign is large-scale long-duration significant military strategy plan incorporating a series of interrelated military operations or battles forming a distinct part of a larger conflict often called a war. The term derives from th ...

historian A historian is a person who studies and writes about the past and is regarded as an authority on it. Historians are concerned with the continuous, methodical narrative and research of past events as relating to the human species; as well as the ...

s to describe what territory was controlled by which side at a given phase of the campaign.

Historical geography

Historical geographers use such techniques in a similar way, but written upon a longer time period. Dated phase lines on a map would indicate the growth or shrinkage of a

great power A great power is a sovereign state that is recognized as having the ability and expertise to exert its influence on a global scale. Great powers characteristically possess military and economic strength, as well as diplomatic and soft power ...

of the era such as the expansion of the

Roman Empire The Roman Empire ruled the Mediterranean and much of Europe, Western Asia and North Africa. The Roman people, Romans conquered most of this during the Roman Republic, Republic, and it was ruled by emperors following Octavian's assumption of ...

, the spread of

Islam Islam is an Abrahamic religions, Abrahamic monotheistic religion based on the Quran, and the teachings of Muhammad. Adherents of Islam are called Muslims, who are estimated to number Islam by country, 2 billion worldwide and are the world ...

Christianity Christianity is an Abrahamic monotheistic religion, which states that Jesus in Christianity, Jesus is the Son of God (Christianity), Son of God and Resurrection of Jesus, rose from the dead after his Crucifixion of Jesus, crucifixion, whose ...

. Other familiar phase line mapping most experience in late elementary or middle school classes would be the extent of various ice ages or the

Ice Age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and g ...

consequential shrinkage or extension of continental landmasses down the continental shelves as the results of such climate changes.

References

{{Reflist Cartography Historical geography Military science Military cartography