GEDCOM

GEDCOM is a specification for exchanging genealogical data between different genealogical systems. GEDCOM is an acronym for GEnealogical Data COMmunication. A GEDCOM file is plain text (often in ASCII in the United States, although technically the standard mandates use of an obscure text encoding named ANSEL) containing records for each individual in the family tree, and data linking these records together.

GEDCOM was developed by The Church of Jesus Christ of Latter-day Saints as an aid in their extensive genealogical research.

Most (if not all) genealogy software supports importing from and/or exporting to GEDCOM format. Additionally, many tools exist to convert GEDCOM files to HTML pages.

Although it is theoretically possible to write a GEDCOM file by hand, the format was designed for export and import by software, and is not especially human-friendly.

Detail
A GEDCOM file consists of a header section, records, and a trailer section.

Records represent people (INDI record), families (FAM records), sources of information (SOUR records), and other miscellaneous records falling into the OTHR category, most notably notes.

Every line of a GEDCOM file begins with a level number, and all top level records (the header, trailer, and each INDI, FAM, SOUR, EVEN, or OTHR) begin with a line with level 0. All other level numbers are positive integers.

Criticism
This file structure handles basic relationship information very well, but it is criticized by some genealogists.

Keeping track of records and events is just as important as keeping track of relationships, but GEDCOM stores these as details under the people and family records. This makes them more difficult to organize and add further details.

Another dilemma is which record should own an event. For example, the record for adoption details could be the child, the adopted parents, the birth parents, or the family the child becomes part of.