خط الطول 180

"Anti-Meridian" redirects here. For the Brave Saint Saturn album, see Anti-Meridian (album).

يجب ألا يـُخلـَط بينها وبين ante meridiem (AM), the time before midday, for which see 12-hour clock.

180th meridian on a map of Earth.

The International Date Line zigzags around the 180th Meridian.

خط الطول 180 أو خط الزوال المقابل antimeridian‏ is the meridian 180° both east and west of the Prime Meridian, with which it forms a great circle dividing the earth into the نصفي الكرة الغربي والشرقي. It is common to both east longitude and west longitude. It mostly passes through the open waters of the Pacific Ocean, but passes across land in Russia, Fiji and Antarctica. This meridian is used as the basis for the International Date Line, but the latter deviates from it to maintain date consistency within the territories of Russia, USA, Kiribati, Fiji and New Zealand.

Starting at the North Pole and heading south to the South Pole, the 180th meridian passes through:

الإحداثيات (تقريبية)	البلد، الإقليم أو البحر	ملاحظات
90°0′N 180°0′E	المحيط القطبي
71°32′N 180°0′E	روسيا	Chukotka Autonomous Okrug — Wrangel Island
70°58′N 180°0′E	Chukchi Sea
68°59′N 180°0′E	روسيا	أوكروگ چوكوتكا الذاتي
65°02′N 180°0′E	بحر برنگ
52°0′N 180°0′E	ممر أمچيتكا	Passing just east of Semisopochnoi Island, ألاسكا, الولايات المتحدة (at 51°57′N 179°47′E)
51°0′N 180°0′E	المحيط الهادي	Passing just east of Nukulaelae atoll,  توڤالو (at 9°25′S 179°52′E) Passing just west of the island of Cikobia, فيجي (at 15°43′S 179°59′W)
16°9′S 180°0′E	فيجي	جزر Vanua Levu, رابي، و Taveuni
16°59′S 180°0′E	المحيط الهادي	يمر مباشرة شرق جزيرة موالا، فيجي (at 18°33′S 179°57′E) Passing just west of the island of توتويا، فيجي (at 19°0′S 179°52′W) Passing just east of the island of Matuku, فيجي (at 19°10′S 179°47′E)
60°0′S 180°0′E	المحيط الجنوبي
78°13′S 180°0′E	أنتارتيكا	Ross Dependency, claimed by نيوزيلندا

180° Meridian, Taveuni, فيجي

The meridian also passes between (but not particularly close to):

• the Gilbert Islands and the Phoenix Islands of Kiribati
• North Island and the Kermadec Islands of نيوزيلندا
• جزر باونتي و جزر تشاتم، أيضاً تابعين لنيوزيلندا

The only place where roads cross this meridian, and where there are buildings very close to it, is in Fiji.

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 مشاكل تمثيل البرمجيات

Many geographic software libraries or data formats project the world to a rectangle; very often this rectangle is split exactly at the 180th meridian. This often makes it non-trivial to do simple tasks (like representing an area, or a line) over the 180th meridian. Some examples:

• The GeoJSON specification strongly suggests splitting geometries so that neither of their parts cross the antimeridian.
• In OpenStreetMap, areas (like the boundary of Russia) are split at the 180th meridian.

 انظر أيضاً

• خط الطول 179 شرق
• خط الطول 179 غرب
• خط الزوال الرئيسي
• خط التاريخ الدولي