Convert to the Mayan Calendar

Identify the epoch (or start date) for the Mayan Long Count calendar as a Julian date.

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epoch = JulianDate["Modified", DateObject[{-3114, 8, 11}, TimeZone -> 0]];

Create a function to convert from Mayan Long Count calendar units to a Julian date.

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JulianFromMayanLongCount[{baktun_, katun_, tun_, uinal_, kin_}] := epoch + 144000*baktun + 7200*katun + 360*tun + 20*uinal + kin

FromJulianDate can be used to test an example input.

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example = JulianFromMayanLongCount[{7, 17, 18, 19, 2}]

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FromJulianDate["Modified", example, TimeZone -> 0]

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Create a function to convert directly from Mayan Long Count to Gregorian date objects.

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GregorianFromMayanLongCount[date_] := DateValue[ FromJulianDate["Modified", JulianFromMayanLongCount[date], TimeZone -> 0], "Day", DateObject]

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GregorianFromMayanLongCount[{7, 17, 18, 19, 2}]

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Create a function to convert from a Julian date to Mayan Long Count calendar units.

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JulianToMayanLongCount[date_] := NumberDecompose[ Floor[date - epoch], {144000, 7200, 360, 20, 1} ]

JulianDate can be used to interpret any date input into a Julian date, which is then fed into JulianToMayanLongCount.

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DateToMayanLongCount[date_] := Block[{$TimeZone = 0}, JulianToMayanLongCount[JulianDate["Modified", date]] ]

This function will now accept any input date and will return the corresponding Mayan Long Count calendar date list.

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DateToMayanLongCount["May 4th, 2015"]

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DateToMayanLongCount[AbsoluteTime[]]

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DateToMayanLongCount[Today]

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These two functions can be used to convert to and from the Long Count Mayan calendar.

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DateToMayanLongCount[{1900, 1, 1}]

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DateToMayanLongCount[{1900, 1, 1}]; GregorianFromMayanLongCount[%]

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