W3C ISO-8601 D.3.2 No Year Zero The year "0000" is an illegal year value.
- Anyone know why ISO-8601 has a year zero.More support for ISO-8601.Great that the ISO-8601 lexical formats rather than C was adopted.
- Yes. ISO 8601 uses the astronomical convention that 1 BCE is the year 0000. This is explained in notes following 188.8.131.52 of the 2000 Draft. This greatly aids computation of time interval from BCE to CE dates, which is important to astronomers.This proposed schema apparently uses year value -0001 to represent 1 BCE, and makes 0000 illegal. So there will be two standards out there, compatible for "current era" dates but not for BCE. Another great step forward.However, one has to ask, "Does it matter?"ISO8601 is really not too useful for dates before the introduction of the Gregorian calendar in 1582. Historians use the Julian calendar before that date because the people of the time used it; they also extend it arbitrarily far into the past before the Julian calendar was established. Dates before 1582 are really history, not commerce, and 8601 is intended to facilitate date interchange in commerce between computers. It is not much used in text in history books. The dates readily available for the period 8 CE to 1582 CE have to be converted from Julian to Gregorian proleptic to use 8601 notation. (from 45 BCE to 8 CE, the Romans had some screwups in leap year determination and it is uncertainly exactly which years were leap years, but the pattern was irregular as they cancelled some leap years to get back on track.)
hjwoudenberg@... wrote:Anyone know why ISO-8601 has a year zero.