Oct 022011

Most genealogy software programs do not adhere to all aspects of the GEDCOM standard.  One subtlety in the standard is the interpretation of “primary” genealogical facts.

When you export a GEDCOM file from your genealogy program, it may not specify primary facts properly.  If it doesn’t, your GED-GEN web pages may display secondary facts instead.

Suppose you found two different dates of birth for a particular individual.  One of the dates is the generally accepted date, but you also want to keep a record of the other date.  You would therefore create two birth facts, one for each date.  Most programs allow you to specify a primary date, which is the date to use in reports and charts.

The GEDCOM file may tell a different story however.  According to the standard:

The occurrence of equal level numbers and equal tags [e.g., BIRTH tags] within the same context imply that multiple opinions or multiple values of the data exist.  The significance of the order in these cases is interpreted as the submitter’s preference.  The most preferred value being the first with the least preferred data listed in subsequent lines by order of decreasing preference.

Unfortunately the standard does not impose an order, except to say the most preferred order is primary first.  However it also gives no mechanism to specify a preferred value except by the order of the tags.  This leaves the door open to genealogy programs to export tags in any order they wish.  Although, the implication is they should list primary facts first.

GED-GEN, being a program that reads GEDCOM files, assumes that primary facts are listed first, followed by secondary facts.  If your genealogy program doesn’t do this, you are likely to see secondary facts displayed in place of primary facts.

Take for instance RootsMagic 4.  It uses a proprietary tag to identify a primary fact, then lists facts in the GEDCOM file in order by date.  If the primary fact date is later than a secondary fact date, the secondary fact is listed first.

Fortunately, RootsMagic allows you to specify the sort order of facts using an internal “sort” date field.  To keep your primary facts sorted in correct order, you must enter sort dates for secondary facts so they appear after the date of the primary fact.  Hopefully this artificial contrivance will apply to only a few cases.  That is, only when the secondary fact date is before the primary fact date will you need to change the “sort” date of the secondary facts.

Confusing, I know.  As a work-around, GED-GEN could look for the RootsMagic-specific tag that indicates a primary fact.  This is something I am considering.

This is not the only subtlety missed by some genealogy programs.  For instance the GEDCOM standard prefers that children in a family record be listed chronologically by birth.  Family Tree Maker ignores this and exports children in a different order.  Here a work-around is more complicated.  Not only would GED-GEN have to parse the birth date of each child, but children that do not have birth dates indicated must be placed in some order.

It’s too bad that you can sort a family’s children in Family Tree Maker, but the ordering is not carried in the GEDCOM file you export.  So if you were to import the same GEDCOM file, the children would no longer be sorted chronologically.

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