AAT ICAS 2042 ✧ UC calculation factors
this document describes AAT ICAS calculation factors for the Uniform Calendar system. please refer to AAT ICAS 2040 for additional important information about calculation factor guidelines.
- Uniform Calendar calculation factors
- table 2042.1 ✧ some Uniform Calendar formula resources
- factoring dates by year, month, day, and daygroup
Uniform Calendar calculation factors
a number of general and specific methods for formatting and factoring dates and times are described in a variety of other resources including operating system documentation, application documentation, UNIX manual pages, APIs for Java and other languages, ISO 8601, and so forth.
developers and users should consider any scale factors among the Uniform Calendar and the Gregorian calendar across common years and leap years. years dated by the Julian calendar should be particularly considered in relation to the New Calendar. the use of a particular method of conversion may involve the following considerations: whether a particular date is derived from a Uniform Calendar date or a Gregorian calendar date; whether the designation or observance of a particular common year or leap-year date is based on a Uniform Calendar or a Gregorian calendar date; and whether the designation or observance of a particular common year or leap-year date is based on a day-of-year, a day-of-month, or a day-of-daygroup scale.
both the Uniform Calendar and the Gregorian calendar scales begin from the first day of a Gregorian calendar year. the day-of-year value is the same for both the Gregorian and Uniform calendars. day-of-year can also be used to calculate of the number of days between calendar dates. the day-of-year number for a day may be indicated by parentheses: UCA 1996(60). however depending on the calendar used and the year type, a particular day-of-year number might correspond to a Uniform Calendar date, a Gregorian common year date, and/or a Gregorian leap year date. the first 59 days in any Gregorian year are not subject to a leap year scale factor, however days 60 through yearend are subject to a leap day factor.
table 2042.1 ✧ some Uniform Calendar formula resources
| resource | formula |
|---|---|
| resource | formula |
| for any day-of-year DoY, for any serial date method for a dateICAS (dateNDN, dateMac, dateWin, and so forth.), for any serial date method for the last day of a prior year dateLP ([YYYY-1]-12-31), for any ordinal uniform month umORD, for any even year yEVEN, for any odd year yODD, for any even year uniform month umEVEN, for any odd year uniform month umODD, for any day-of-uniform month DoUM, (please refer also to AAT ICAS 2041 and -2043 formula resources): | |
| day-of-year | DoY = dateICAS - dateLP. |
| ordinal uniform month | IF (DoY/30) rounded up to next integer is LESS THAN 12, THEN umORD is (DoY/30) rounded up to next integer, ELSE umORD is 12. |
| uniform month for yEVEN | IF umORD is 1, then uniform month is A; etc. (per AAT ICAS 3120). |
| uniform month for yODD | IF umORD is 1, then uniform month is N; etc. (per AAT ICAS 3120). |
| even or odd year rule | IF (yNC/2) = INTEGER(yNC/2), THEN yNC is even, ELSE yNC is odd. |
| day-of-uniform month | DoUM = DoY - (umORD * 30) + 30. |
| special note: ensure that numerical expressions are represented to an appropriate number of places, even if the beginning places are leading zeroes. | |
Uniform Calendar calculation factors
referencing calendar dates by day of year can involve noting which method of leap day intercalation is used. in the Gregorian calendar, leap days are intercalated on day-of-year 060 (February 29) each Gregorian calendar leap year. in the Uniform Calendar, leap days are intercalated on day-of-year 366 (M36 corresponding to December 31) each Gregorian calendar leap year. Gregorian calendar dates thus correspond to day-of-year dates depending on whether the years for the reference or schedule dates are leap or common years.
for example the United States Declaration of Independence was signed in a leap year on 1776 July 04 corresponding to day-of-year 186. in leap years July 04 corresponds to day-of-year 186. in common years July 04 however corresponds to day-of-year 185.
Independence Day in the United States is customarily observed as 'Independence Day' or as the 'Fourth of July'. the day-of-week daygrouping is not usually considered except for determining whether the holiday schedules would occur on or adjacent to a weekend.
the Gregorian calendar date 1776 July 04 corresponds to Uniform Calendar date UCN 11776G06. day-of-year 186 corresponds to the uniform month dates G06 in even-numbered years and U06 in odd-numbered years. each year the date occurs on the 6th day of a block daygroup, blockday Orange, the first block of the 7th uniform month G-U (the block following the monthend for the 6th uniform month F-T).
aatideas.org document updated:
| scale | value | ||
|---|---|---|---|
| UCN | 12019 S19 Yellow | ||
| zone(UT) | t339 tt050 | ||
| 'ICAS in use' can accommodate calendar and clock formatting 'for all people, for all time'. | |||
| AD common year day | 139 | ||
| G | 2019 May 19 Sunday | ||
| UT | 08:08:14 | ||
| style legend | |||
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