Longitude

Definition

Longitude is a geographical coordinate that specifies the east-west position of a point on the Earth's surface, measured in degrees from the Prime Meridian, which is defined as 0 degrees longitude. This concept is crucial for navigation and cartography, as it allows for the precise location of places on maps and in navigation systems, enabling travelers to determine their position relative to other locations worldwide.

5 Must Know Facts For Your Next Test

1. Longitude lines run vertically from the North Pole to the South Pole and are often referred to as meridians.
2. Each degree of longitude corresponds to approximately 69 miles (111 kilometers) at the equator but varies in distance as one moves toward the poles.
3. The International Date Line, located at approximately 180 degrees longitude, serves as the boundary for calendar days, marking where one day ends and another begins.
4. Navigators traditionally used celestial navigation methods to determine longitude by measuring the angle between a celestial body and the horizon.
5. The invention of the marine chronometer in the 18th century significantly improved the ability to calculate longitude accurately at sea.

Review Questions

• How does longitude play a role in determining geographic locations and why is it essential for navigation?
  • Longitude provides a systematic way to pinpoint locations on Earth by defining their east-west position. It works alongside latitude to create a grid system that allows navigators and mapmakers to chart courses accurately. By knowing both latitude and longitude, travelers can navigate effectively across vast distances, ensuring they reach their intended destinations without getting lost.
• Discuss how advancements in technology have impacted the methods used to measure longitude over time.
  • Advancements in technology, particularly with the introduction of marine chronometers in the 18th century, revolutionized how sailors measured longitude. Prior to this, navigators relied on celestial navigation methods which were often inaccurate and difficult to perform at sea. Today, global positioning systems (GPS) provide real-time longitude data with incredible precision, making navigation much simpler and more reliable than ever before.
• Evaluate the implications of varying distances between lines of longitude as one approaches the poles, especially concerning global navigation.
  • As one moves from the equator toward the poles, the distance between lines of longitude decreases significantly. This variation means that while each degree of longitude at the equator covers about 69 miles (111 kilometers), it converges to nearly zero at the poles. This has critical implications for global navigation; navigators must be aware of this convergence when plotting courses and may need to adjust their strategies when traveling in polar regions where traditional navigation might become less effective due to closely packed meridians.

Related terms

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

Prime Meridian: The Prime Meridian is the meridian (0 degrees longitude) from which all other longitudes are measured, running through Greenwich, England.

Time Zones: Time zones are regions of the Earth that have the same standard time, established based on longitudinal divisions, affecting local time based on position relative to the Prime Meridian.