{"title":"Generate a Mayan chart","fields":[{"key":"date","name":"date","kind":"date","required":true,"description":"Date in YYYY-MM-DD format, in the PROLEPTIC GREGORIAN calendar, extended backwards unchanged through the 1582 reform. Years 1 to 4000 are accepted. A reference converter that switches to the Julian calendar below the reform will disagree with a date before 15 October 1582 by ten or eleven days; that is a difference of input convention rather than of arithmetic, and passing the Julian equivalent to such a tool reproduces these values exactly. A single-digit month or day is accepted and zero padded.","example":"2012-12-21"},{"key":"correlation","name":"correlation","kind":"tiles","required":false,"description":"Which correlation constant ties the day count to a civil date. This is the single choice that shifts every value in the response, so it is a parameter rather than a hidden default, and the resolved value comes back under conventions. \"gmt-584283\" is the commonly accepted constant and the default, and it is the one the major institutional converter runs on. \"martinez-hernandez-584281\" sits two days earlier, \"astronomical-584285\" two days later, and \"martin-skidmore-584286\" three days later, each shifting the Long Count by exactly its difference in days. Four of the eight published constants are offered: the other four sit tens of thousands of days away and are of historical interest only. The 584281 constant is the Martínez Hernández correlation, after Juan Martínez Hernández.","enum":["gmt-584283","martinez-hernandez-584281","astronomical-584285","martin-skidmore-584286"],"default":"gmt-584283","example":"gmt-584283","fold":true},{"key":"yearBearerSystem","name":"yearBearerSystem","kind":"tiles","required":false,"description":"Which Haab day is read as the start of the year when naming its Year Bearer. Only four of the twenty day signs can ever carry a year, and which four depends entirely on this choice, so the three schools never agree. \"classic\" reads the seating of Pop and is the default, because it is the set highland daykeepers still use; its four bearers are Ikʼ, Manikʼ, Ebʼ and Kabʼan. \"campeche\" reads 1 Pop and gives Akʼbʼal, Lamat, Bʼen and Etzʼnabʼ. \"colonial-yucatec\" reads 2 Pop and gives Kʼan, Muluk, Ix and Kawak. The three sets share no member, so a bearer alone tells you which school produced it.","enum":["classic","campeche","colonial-yucatec"],"default":"classic","example":"classic","fold":true}],"hasLang":true,"groups":[{}],"opensOnLoad":false}