Definition
The 25th meridian west is a line of longitude that is 25 degrees west of the Prime Meridian at Greenwich, England. It extends from the North Pole to the South Pole, forming part of the Earth's longitudinal coordinate system.
Overview
As one of the 360 meridians that divide the globe into equal angular segments, the 25th meridian west traverses several geographic regions and bodies of water. Beginning at the North Pole, it passes through the Arctic Ocean, intersects the eastern coast of Greenland, continues across the North Atlantic Ocean, crosses the equatorial Atlantic, and proceeds through the Southern Ocean before reaching Antarctica. The meridian is paired with its antimeridian, the 155th meridian east, to form a complete great circle.
Etymology/Origin
The term “25th meridian west” derives from the naming convention for longitudinal lines, which are numbered in degrees east or west from the Prime Meridian. The number 25 indicates its angular distance of 25° from Greenwich, while “west” designates the direction relative to the Prime Meridian.
Characteristics
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Geographic Path:
- Arctic Region: Crosses the Arctic Ocean.
- Greenland: Intersects the eastern shoreline near the region of the Scoresby Sound.
- Atlantic Ocean: Extends through the central North Atlantic, passing east of the Azores archipelago (the westernmost Azorean islands lie near 25°W).
- Equatorial Zone: Continues through the tropical Atlantic without intersecting major landmasses.
- Southern Ocean and Antarctica: Enters the Southern Ocean and crosses the Antarctic continent within the sector claimed by the United Kingdom as the British Antarctic Territory (though such claims are held in abeyance under the Antarctic Treaty).
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Great‑Circle Relationship: Forms a great circle with the 155th meridian east, together encompassing a full 360° around the globe.
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Navigation and Cartography: Utilized in geodetic surveys, navigation, and mapmaking to pinpoint locations east or west of Greenwich. The meridian appears on most global coordinate grids and is referenced in aviation and maritime charting.
Related Topics
- Prime Meridian – The 0° longitude line from which east and west longitudes are measured.
- Lines of Latitude – Horizontal lines that, together with meridians, create the geographic coordinate system.
- Great Circle – The largest possible circle that can be drawn on a sphere, formed by any meridian and its antimeridian.
- Greenland – The world’s largest island, intersected by several meridians including the 25th west.
- Antarctic Treaty System – The international agreement governing territorial claims and activities in Antarctica, relevant to the meridian’s passage through the continent.