Nautical time communicating with land, the land time zone must be employed. The nautical time zone system is an ideal form of the terrestrial time zone system for use on high seas. Under the system time changes are required for changes of longitude in one-hour steps. The one-hour step corresponds to a time zone width of 15° longitude. The 15° gore that is offset from GMT or UT1 (not UTC) by twelve hours is bisected by the nautical date line into two 7°30′ gores that differ from GMT by ±12 hours. A nautical date line is implied but not explicitly drawn on
The Equator monument The Equator monument The Equator monument is located on the equator in Pontianak, Indonesia. It marks the division between the northern and southern hemispheres. The monument consists of four iron wood poles, each with a diameter of about 0,30 metre, with frontage bollard height is two pieces as high as 3,05 radian place backside bollard and the signpost dart as high as 4,40 metres. Its location is in "Jalan Khatulistiwa", North Pontianak, about 3 kilometres from the city centre of Pontianak. The equator monument is not on the equator any more. The equator has moved slightly southwards and there is