Subject: GEDCOM date‑constraint semantics should not be propagated into Gramps First of all, apologies for raising this here, but I’ve recently become aware of a fairly serious issue in how dates are handled — both in GEDCOM and, as far as I can tell, also in Gramps. Because this PR touches the sam…

[image] StoltHD: A historical After 1850 means “sometime after the end of 1850”. GEDCOM’s Not Earlier Than 1850 means “starting at the beginning of 1850”. “AFT 1850” is “AFT (BET 1 JAN 1850 AND 31 DEC 1850)”. And that is for me logically “AFT 1 JAN 1850”. Your historical definition is for me…

The semantics of this get complex AFT 1850 is any date greater than the 23:59:59 on the 31st Dec 1850 BEF 1850 is any date less than 00:00:00 on the 1st Jan 1850 That is why I would prefer to use the mathematical symbols is AFT as above = is AFT 00:00:00 on the 1st Jan 1850 < is BEF as above …

AFT (After) 1850 does not mean “after 1 January 1850”. It means “after the year 1850 has ended”. In historical, chronological, and mathematical logic: The year 1850 represents the interval [1850‑01‑01, 1850‑12‑31] Therefore: AFT (After) 1850 means a date > 1850‑12‑31 The first valid date is 18…

[image] comeng: The semantics of this get complex AFT 1850 is any date greater than the 23:59:59 on the 31st Dec 1850 BEF 1850 is any date less than 00:00:00 on the 1st Jan 1850 That is why I would prefer to use the mathematical symbols is AFT as above = is AFT 00:00:00 on the 1st Jan 1850 …

[image] StoltHD: The year 1850 represents the interval [1850‑01‑01, 1850‑12‑31] Are you sure? If Fred is born in 1850, he is not born in an intervall. He is born at a spefic point in time, but the exact day and month are unknown. It is a point - not a period, not a range Temporal precision …

Yes I am sure… a birth is a point in time, but when only the year is known, that point must lie somewhere within the interval [1850‑01‑01, 1850‑12‑31]. The year is the interval, the birth is the point inside the interval. And following the same logic: If Fred is born “in 1850”, then he must have …

Thanks Phil — and yes, with your updated symbols we are actually saying the same thing. If AFT 1850 is meant to be “after the end of 1850”, then the earliest possible point is > 1850‑12‑31. If you write “>= 1 Jan 1850”, that instead includes the entire year 1850, which contradicts the definition abo…

I just want to make sure that everyone in this discussion is aware that the definitions of GEDCOM’s AFT and BEF changed with GEDCOM 7.0. In last August, I wrote the following summary. Please refer to the links for further background info. [image] Misleading date range labels? (Before, After, Betw…

[image] FamilySearch Integration PR The year 1850 represents the interval [1850‑01‑01, 1850‑12‑31] Yes I am sure… a birth is a point in time, but when only the year is known, that point must lie somewhere within the interval [1850‑01‑01, 1850‑12‑31]. The year is the interval, the birth is the…

GEDCOM date‑constraint semantics should not be propagated into Gramps

Development

comeng March 29, 2026, 3:49pm 7

I actually wrote

> is AFT as above
>= is AFT 00:00:00 on the 1st Jan 1850
< is BEF as above
<= is BEF 23:59:59 on the 31st Dec 1850

but it seems to have got truncated
phil

FamilySearch Integration PR

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GEDCOM date‑constraint semantics should not be propagated into Gramps

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