World clock
A world clock is a clock that displays the time from many or all time zones around the world. During World Time watches were mainly in the last decades of larger installations, there are some years more and more digital models that take into account some of which fit on a desk or even on your wrist and the eventual date with changes.
The simple at first glance, divided into 24 time zones is complicated by differing local daylight saving time changes and half-hour steps in the Asian region.
States define legal time in their territory with a fixed offset from Coordinated Universal Time (UTC). This offset is usually equal to a whole number of hours, but some countries use an offset half-hour or quarter hour.
In general, countries tend to use a time zone so that the mean solar time on their territory is not too far from the standard time (that is to say, for example, for lunch Solar is not too far from twelve o'clock legal). This principle has many exceptions, however:
A country usually has a single standard time, for obvious reasons of unification of the hour. It can ignore the limit of a zone if its territory encroaches slightly on the time neighbor: this is the case of Germany to the west of Sweden or to the east. At the extreme, some countries may even, although covering several time, adopt a single standard time: the case of China and India.
Some major countries (Australia, Brazil, Canada, Congo, USA, Indonesia, Russia, etc..) Are arbitrarily divided into several zones to avoid too great a difference between the standard time and solar time: the limit the application of local standard time generally follows the boundaries of the area or state and can thus be positively offset from the edge of the zone of origin. This is also the case of certain remote dependencies, such as the DOM-TOM French, the Portuguese Azores, etc..
A country may adopt a time zones other than that which would be designed a priori. This is the case of the Spanish mainland or mainland France that are local to central Europe, so in one hour ahead of the time in which is the largest part of their territory. Thus, in France, only the extreme east of the country (Alsace, Corsica) is in the zone corresponding to the standard time, while Spain (excluding Canary Islands) has no part of its territory in the time which she has the time, and even some in the far west (Galicia) which is two time ago.
Some countries have chosen a time not corresponding to an entire shift with UTC. This is usually a lag of a number of half-hour (UTC +3:30 Iran, Afghanistan to UTC +4:30, India to UTC +5:30), even if only Nepal's shift hours (UTC +5:45).
Part of the world uses a system of daylight saving and standard time, created to achieve energy savings (and sometimes criticized). The legal time may well, for several months of the year, largely be offset from the time of the initial time. Note that two different hemispheres of countries observing daylight saving time shift is also summer in the Southern hemisphere world clock map corresponding to the Northern Hemisphere winter.
The simple at first glance, divided into 24 time zones is complicated by differing local daylight saving time changes and half-hour steps in the Asian region.
States define legal time in their territory with a fixed offset from Coordinated Universal Time (UTC). This offset is usually equal to a whole number of hours, but some countries use an offset half-hour or quarter hour.
In general, countries tend to use a time zone so that the mean solar time on their territory is not too far from the standard time (that is to say, for example, for lunch Solar is not too far from twelve o'clock legal). This principle has many exceptions, however:
A country usually has a single standard time, for obvious reasons of unification of the hour. It can ignore the limit of a zone if its territory encroaches slightly on the time neighbor: this is the case of Germany to the west of Sweden or to the east. At the extreme, some countries may even, although covering several time, adopt a single standard time: the case of China and India.
Some major countries (Australia, Brazil, Canada, Congo, USA, Indonesia, Russia, etc..) Are arbitrarily divided into several zones to avoid too great a difference between the standard time and solar time: the limit the application of local standard time generally follows the boundaries of the area or state and can thus be positively offset from the edge of the zone of origin. This is also the case of certain remote dependencies, such as the DOM-TOM French, the Portuguese Azores, etc..
A country may adopt a time zones other than that which would be designed a priori. This is the case of the Spanish mainland or mainland France that are local to central Europe, so in one hour ahead of the time in which is the largest part of their territory. Thus, in France, only the extreme east of the country (Alsace, Corsica) is in the zone corresponding to the standard time, while Spain (excluding Canary Islands) has no part of its territory in the time which she has the time, and even some in the far west (Galicia) which is two time ago.
Some countries have chosen a time not corresponding to an entire shift with UTC. This is usually a lag of a number of half-hour (UTC +3:30 Iran, Afghanistan to UTC +4:30, India to UTC +5:30), even if only Nepal's shift hours (UTC +5:45).
Part of the world uses a system of daylight saving and standard time, created to achieve energy savings (and sometimes criticized). The legal time may well, for several months of the year, largely be offset from the time of the initial time. Note that two different hemispheres of countries observing daylight saving time shift is also summer in the Southern hemisphere world clock map corresponding to the Northern Hemisphere winter.