Open map List

Longditude

In cartography, longitude refers to the angular distance of a point east or west of the Prime Meridian. It is measured in degrees (°) from 0° at the Prime Meridian to 180° east and 180° west.

Basic

Introduction

Key Characteristics of Longitude:

  1. Meridians – Longitude lines (also called meridians) run north to south, but measure distances east or west of the Prime Meridian.
  2. Degrees and Minutes – Longitude is expressed in degrees (°), minutes ('), and seconds (").
  3. Fixed Reference Points:
    • Prime Meridian (0° Longitude) – Passes through Greenwich, England, and serves as the starting point for measuring longitude.
    • International Date Line (180° Longitude) – The line opposite the Prime Meridian, marking the change of calendar days.
    • Eastern Hemisphere (0° to 180° E) – Includes Europe, Asia, Africa, and Australia.
    • Western Hemisphere (0° to 180° W) – Includes the Americas and parts of the Pacific Ocean.

Explanation

Importance of Longitude in Cartography:

  • Time Zones – Longitude determines standard time zones worldwide.
  • Navigation and GPS – Longitude coordinates help pinpoint exact locations on Earth when combined with latitude.
  • Map Projections – Longitude plays a role in the distortion and accuracy of different map projections.

Examples

Longitude and Geographic Coordinates:

  • Longitude is used alongside latitude to define precise locations in a geodetic system (e.g., WGS84, used in GPS).
  • Expressed in:
    • Decimal Degrees (e.g., -122.4194° W).
    • Degrees, Minutes, and Seconds (DMS) (e.g., 122°25'10" W).

Outgoing relations