Time Zone Map

The planet Earth is divided into a specific number of time zones. A majority of these existing time zones are seen as exactly one hour apart which results in calculating their local times by a convection of a direct offset from Coordinated Universal Time(UTC) or Greenwich Mean Time(GMT). Due to the various locations these experienced offsets were seen to differ twice each year as a result of Daylight Saving Time conversions.
The base factor for modern civil time has often been referred to as Coordinated Universal Time. This Universal time ever since January 1st 1972 has similarly been defined by the International Atomic Time with a precise number of seconds observing its only change whenever a leap second is required to maintain accurate synchronization of the Earth’s rotation.
Recognized as a seemingly older standard of time Greenwich Mean Time originated in 1847 with the introduction of the British Railroad. This system was effectively recognized as the world’s time standard in 1884 at the Washington Conference during which the 24 hour time zone system evolved.

By using devices such as telescopes, Greenwich Mean Time was accurately calibrated at the Royal Observatory in the United Kingdom to reflect solar time. Greenwich Mean Time was successfully calculated for the first time by using a 24 hour clock beginning at noon. This older standard however was replaced by the International Astronomical Union in 1928 by the Universal Time which was based on the International telescope-based system.
Astronomical observations came to a halt at the Greenwich Observatory in 1954 which saw the facility being used for the sole purpose of system coordination. Due to the Earth’s perfectly constant rotation on it’s axis the existence of a secondary variable when calibrated to a telescopic base standard would result in the definition of a second as a fraction of a year.
Such a time zone is generally referred to as a specific region on the planet Earth which can typically be found as bounded by uniform lines of longitude. These lined of longitude are legally mandated as specific units of time and as such are referred to as local time within that specific region. The Earth is divides into 24 main time zones which are effectively used to calculate the local time as an offset from the Coordinated Universal Time.
Each of these time zones consist of a boundary which gives the distinct impression in appearance of 15 degrees in an easterly or westerly direction of the other. The reference point used in calculation of the Coordinated Universal Time is known as the Greenwich Meridian otherwise called the Prime Meridian which is seen as having a specific longitudinal value of 0 degrees.
The local time in any specific region is calculated by adding the Coordinated Universal Time or UTC with the local time experienced within the specific region or the location in question.
The corresponding hourly value relative to the Coordinated Universal time is seen as an advance in hourly value relative to every increment of 15 degrees when headed in a westerly direction and similarly will be observed in a loss of an hour for every 15 degree longitudinal value when headed in an easterly direction towards the International Date Line.