The International date lineInternational Date Line
In this article we describe the International Date Line, how it was created and why it is used.
Internacional date line map and explanation
On the 180º length in the centre of the Pacific Ocean, the International Date Line is the fictive line that divides two successive calendars. This is not a completely flat line and has been shifted slightly over the years to meet the needs (or wishes) of the various Pacific Ocean states.
Notice how it curves to extend all of Kiribati, Samoa, Tonga and Tokelau into the Eastern Hemisphere. Just to the lefthand side of the International Date Line, the date is always one of the days before the date (or day) immediately to the right of the International Date Line in the western hemisphere.
In the times and dates shown below, please be aware that Tonga and American Samoa have the same period, but are one date apart, as American Samoa is located in the western hemisphere, on the opposite side of the Tonga International Date Line. If you continue your journey to the western part, please bear in mind that the journey in Fiji is one hours sooner than in Tonga.
You' ll also find that Hawaii, further eastwards from American Samoa, lies an an hour later. So if you drive eastwards across the International Date Line, one or 24 hrs will be deducted. The westbound crossing of the International Date Line leads to the addition of one tag. This global co-ordinated world clock system, formerly known as GMT (Greenwich Mean Time), is now shortened to ULT (Coordinated General Time).
Normally, this is the default timezone on which all other global timezones are located. Never observing summer times.
International Date Line
International Date Line is the fictive line on Earth that divides two successive dates. This means that the date in the eastern hemisphere, to the lefthand side of the line in the illustration, is always one date before the date in the eastern hemisphere. 2. This has been recognised as a question of comfort and is not valid under international legislation.
If the International Date Line were not available, travellers heading west would find that on their return home they had one extra full working week than they thought, even though they had carefully recorded the time. It can be anywhere in the world. In the course of the years, the International Date Line has undergone several changes.
Up until 1845, the Philippines was on the east side of the country (on the same side as the United States). They were on the east side of the line because it was a Spaniard settlement and most Europeans came to South America through the Spaniards. Indonesia was thus located to the western side of the International Date Line.
Following the independency of the Latin America nations, most of the Philippines travelled through the Cape of Good Hope, so it was agreed to move from the eastern part of the line to the western part of the line. Alaska was initially asserted by Russia and was situated just westwards of the International Date Line because most travellers came there via Siberia.
In 1867, when the United States purchased Alaska, the line was relocated to the Northwest. Kiribati relocated a large part of it to the eastern part in 1995, so that the whole country was on the same side of the International Date Line. The line thus lies up to 150 degrees eastwards, further eastwards than Honolulu.
Last line modification was at 31 December 2011 (local time) at midnight1, when Samoa left the east to the west side of the International Date Line. Like all other changes to the International Date Line, the amendment was made by a country that has a strong sense of responsibility for the area.
Most of the cards show the line of the British Admiralty in 1921.