## Re: [Gramps-devel] Proposed date/calendar changes

 Re: [Gramps-devel] Proposed date/calendar changes From: James A. Treacy - 2002-12-26 04:16:02 ```Speaking of dates, one thing that has bothered me is that there is no way to separate uncertaintity in the from uncertaintity in the day of the year. For example there is no way to handle a person who was born on March 13 but you are unsure of the year(*). (*)If I am incorrect, how should this be entered? -- James (Jay) Treacy treacy@... ```

 Re: [Gramps-devel] Proposed date/calendar changes From: Lars Kr.Lundin - 2002-12-25 22:32:15 ```Thanks for coming up with these ideas. I think the idea of separating the date and the calendar and to associate the date validation with the calendar is very good. Allow me to elaborate on the internal date-representation. GEDCOMP (my genealogy database) handles dates internally using interval arithmetic (a concept from numerical analysis). Basically, something like a point in time is represented not as a real number but as an interval (ie. a lower and an upper bound) in which the actual value is guaranteed to lie. Pretty much anything that one can do to a real number can be defined to also apply to such an interval. Interval arithmetic is useful for handling not only inaccurate representation of real numbers (like in a computer) but also for f.ex. inexact date-information in genealogy. I would expect an interval-arithmetic library with python bindings to exist. GEDCOM DATEs like 1712 DEC 2002 BET 1800 AND 1850 25 DEC 2002 are all intervals (the last has equal lower and upper bound). AFT 1900 is also an interval - an open-ended one (with infinity as upper bound). When an event described by an AFT-date is known to have happened (like someones birth and notably not a living persons death) the interval can be upper-bounded with some date (like todays date or the creation date of the GEDCOM). Trying to entirely avoid open-ended intervals in this way could however prove too restrictive. In genealogy it is useful to be able to handle inexact interval bounds. Consider a person X who died in 1770 with a son approximately 30 years old. The upper bound of X's death date is 31 DEC 1770 whereas the lower bound is ABT 1740. For the DATE ABT 1780 both the lower (1 JAN 1780) and upper (31 DEC 1780) bound is inexact. One could argue that the time-range (GEDCOM FROM-TO construction) really should be described by two intervals, the first marking the start date of the time-range, the second marking the end. I agree that it is sufficient to instead mark the interval as a range. Consider f.ex. person Y who lived in London from 1066 to ABT 1111. The lower bound (year 1066) is really an interval (with a point in time between 1 JAN 1066 and 31 DEC 1066), but all we can say for sure is that Y lived in London from 31 DEC 1066. So the upper bound of the starting interval and the lower bound of the ending interval that form the range are really all that are useful. So I think the best way to represent a piece of date-information internally is by A) its calendar B) its lower bound date (always year-month-day) with a ternary indicator with the possible values: exact, about and (minus) infinity (for BEFore) C) its upper bound date (always year-month-day) with a ternary indicator with the possible values: exact, about and infinity (for AFTer) D) a range flag for when the state is true throughout the interval, ie. to distinguish between f.ex. 1 NAME Alive /Today/ 1 DEAT 2 DATE AFT 25 DEC 2002 and 1 NAME Dead /Today/ 1 DEAT 2 DATE FROM 25 DEC 2002 I have just reread the Date object description and now I wonder if there is any difference at all between 1)-4) and the above A)-D). If 1)-4) describes the same as A)-D) then at least I hope that others than myself have gotten a better understanding of the internal date- representation in GRAMPS. > Regional differences can be handled by different calendars. For > example, if Region1 and Region2 had two different switch points > between the Julian and Gregorian calenadars, the could be represented > by two different calendars, such as 'Julian (Region1)' or 'Julian > (Region2)'. Very nice. Thank you, -Lars Lundin. -- GEDCOMP: An extensive and free database for genealogists with interest in Denmark: http://www.lklundin.dk/gedcomp/ ```
 Re: [Gramps-devel] Proposed date/calendar changes From: Lars Kr.Lundin - 2002-12-26 09:31:14 ```On Wed, Dec 25, 2002 at 09:27:18PM -0700, Don Allingham wrote: > This can be handled now by using a '?' for the date. Try entering a date > in one of the following formats: > > March 13, ? > A subsequent GEDCOM-export (using v. 0.8.1-1) results in an invalid line 2 DATE 13 MAR ???? When the year is not recognizable the DATE_VALUE should be (), ie. the above could be better exported as 2 DATE (13 MAR) -Lars Lundin. -- GEDCOMP: An extensive and free database for genealogists with interest in Denmark: http://www.lklundin.dk/gedcomp/ ```
 Re: [Gramps-devel] Proposed date/calendar changes From: Don Allingham - 2002-12-26 16:29:46 ```Lars, Thanks for the information. I will fix this. Don On Thu, 2002-12-26 at 02:33, Lars Kr.Lundin wrote: > On Wed, Dec 25, 2002 at 09:27:18PM -0700, Don Allingham wrote: > > > This can be handled now by using a '?' for the date. Try entering a date > > in one of the following formats: > > > > March 13, ? > > > > A subsequent GEDCOM-export (using v. 0.8.1-1) results in an invalid line > > 2 DATE 13 MAR ???? > > When the year is not recognizable the DATE_VALUE should be > (), ie. the above could be better exported as > > 2 DATE (13 MAR) > > -Lars Lundin. > -- > GEDCOMP: An extensive and free database for genealogists with > interest in Denmark: http://www.lklundin.dk/gedcomp/ > > > ------------------------------------------------------- > This sf.net email is sponsored by:ThinkGeek > Welcome to geek heaven. > http://thinkgeek.com/sf > _______________________________________________ > Gramps-devel mailing list > Gramps-devel@... > https://lists.sourceforge.net/lists/listinfo/gramps-devel -- Don Allingham GRAMPS - Open Source Genealogy ```
 Re: [Gramps-devel] Proposed date/calendar changes From: James A. Treacy - 2002-12-26 04:16:02 ```Speaking of dates, one thing that has bothered me is that there is no way to separate uncertaintity in the from uncertaintity in the day of the year. For example there is no way to handle a person who was born on March 13 but you are unsure of the year(*). (*)If I am incorrect, how should this be entered? -- James (Jay) Treacy treacy@... ```
 Re: [Gramps-devel] Proposed date/calendar changes From: Don Allingham - 2002-12-26 04:28:08 ```Jay, This can be handled now by using a '?' for the date. Try entering a date in one of the following formats: March 13, ? or 2/13/? Don On Wed, 2002-12-25 at 21:15, James A. Treacy wrote: > Speaking of dates, one thing that has bothered me is that there is no > way to separate uncertaintity in the from uncertaintity in the day of > the year. For example there is no way to handle a person who was born > on March 13 but you are unsure of the year(*). > > (*)If I am incorrect, how should this be entered? > > -- > James (Jay) Treacy > treacy@... > > > ------------------------------------------------------- > This sf.net email is sponsored by:ThinkGeek > Welcome to geek heaven. > http://thinkgeek.com/sf > _______________________________________________ > Gramps-devel mailing list > Gramps-devel@... > https://lists.sourceforge.net/lists/listinfo/gramps-devel > ```
 Re: [Gramps-devel] Proposed date/calendar changes From: James A. Treacy - 2002-12-26 20:14:14 ```On Wed, Dec 25, 2002 at 09:27:18PM -0700, Don Allingham wrote: > Jay, > > This can be handled now by using a '?' for the date. Try entering a date > in one of the following formats: > > March 13, ? The specific example that started me on this was of the form March 13, 1800/1801. Is there a way to do that? -- James (Jay) Treacy treacy@... ```
 Re: [Gramps-devel] Proposed date/calendar changes From: Don Allingham - 2002-12-26 20:28:20 ```Not yet. I will give it some thought on the right way to handle this. Don On Thu, 2002-12-26 at 13:13, James A. Treacy wrote: > On Wed, Dec 25, 2002 at 09:27:18PM -0700, Don Allingham wrote: > > Jay, > > > > This can be handled now by using a '?' for the date. Try entering a date > > in one of the following formats: > > > > March 13, ? > > The specific example that started me on this was of the form > March 13, 1800/1801. Is there a way to do that? -- Don Allingham GRAMPS - Open Source Genealogy ```