Longitude

Definition

Longitude is the geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is measured in degrees, with the Prime Meridian at 0 degrees serving as the reference line. Understanding longitude was crucial for navigation, allowing sailors to determine their position relative to the Earth and thus successfully traverse oceans and establish trade routes.

5 Must Know Facts For Your Next Test

1. Longitude is measured in degrees from 0° to 180°, both east and west of the Prime Meridian, affecting navigation and cartography.
2. Accurate determination of longitude at sea was historically challenging until the invention of reliable chronometers in the 18th century.
3. Sailors used lunar observations and star positions to estimate longitude before technological advancements made calculations easier.
4. The establishment of time zones is linked to lines of longitude, with each zone typically spanning 15 degrees of longitude representing one hour's difference in solar time.
5. Longitude lines run from pole to pole and are not parallel, converging at the poles, which is important for accurate mapmaking.

Review Questions

• How did advancements in navigational instruments improve sailors' ability to determine longitude during voyages?
  • Advancements like the marine chronometer revolutionized navigation by allowing sailors to accurately keep track of time at sea. This precise timekeeping enabled them to calculate their longitude by comparing local time with Greenwich Mean Time. Before these instruments were developed, sailors relied on less accurate methods such as celestial navigation techniques, which often led to errors in determining their exact position.
• Discuss the navigational challenges that arose from inaccurate determination of longitude and how they affected maritime exploration.
  • Inaccurate determination of longitude posed significant challenges for maritime explorers, often resulting in ships becoming lost or missing their intended destinations. Explorers faced difficulties in charting courses across vast oceans, leading to dangerous situations such as shipwrecks and unplanned landfalls. The inability to accurately calculate longitude hampered trade routes and exploration efforts, highlighting the critical need for reliable navigational tools that ultimately spurred innovation in this area.
• Evaluate the impact of latitude and longitude on early mapmaking practices and how they shaped our understanding of geography.
  • The introduction of latitude and longitude fundamentally transformed early mapmaking practices by providing a systematic way to represent geographic locations. By incorporating these coordinates, mapmakers could create more accurate and detailed representations of the world. This precision not only improved navigation but also expanded European knowledge of global geography, facilitating trade and exploration during the Age of Exploration. As maps became more accurate due to these advancements, they laid the groundwork for future developments in cartography and geographic understanding.

Related terms

Prime Meridian: The Prime Meridian is the zero-degree line of longitude that runs from the North Pole to the South Pole, passing through Greenwich, England.

Latitude: Latitude is the geographic coordinate that specifies the north-south position of a point on the Earth's surface, measured in degrees north or south of the equator.

Chronometer:

A chronometer is a precise timekeeping device essential for determining longitude at sea by measuring time differences between a known location and the current location.