GEDCOM

From Wikipedia, the free encyclopedia
Jump to: navigation, search
GEDCOM
Filename extension .ged
Developed by LDS FHD
Initial release 1984 (1984)
Latest release GEDCOM 5.5 Standard + Errata Sheet  / 2 January 1996; 18 years ago (1996-01-02)
Type of format Genealogy data exchange
Standard De facto[1]
Website gedcom.org (Historical)

GEDCOM (an acronym standing for Genealogical Data Communication) is a proprietary and open de facto[1] specification for exchanging genealogical data between different genealogy software. GEDCOM was developed by The Church of Jesus Christ of Latter-day Saints (LDS Church) as an aid to genealogical research.[2]

A GEDCOM file is plain text (usually either ANSEL or ASCII) containing genealogical information about individuals, and meta data linking these records together. Most genealogy software supports importing from and/or exporting to GEDCOM format.[3] However, some genealogy software programs incorporate the use of proprietary extensions to the GEDCOM format, which are not always recognized by other genealogy programs, for example the GEDCOM 5.5 EL (Extended Locations) specification.[4][5][6]

In February of 2012 at the RootsTech 2012 conference, FamilySearch outlined a major new project around genealogical standards called GEDCOM X, and invited collaboration.[7] In August of 2012 FamilySearch employee and GEDCOM X project leader Ryan Heaton dropped the claim that GEDCOM X is the new industry standard, and repositioned GEDCOM X as another FamilySearch open source project.[8]

GEDCOM model[edit]

GEDCOM uses a lineage-linked data model. This data model is based on the nuclear family and the individual. This contrasts with evidence-based models, where data are structured to reflect the supporting evidence. In the GEDCOM lineage-linked data model, all data are structured to reflect the believed reality, that is, actual (or hypothesized) nuclear families and individuals.

GEDCOM file structure[edit]

A GEDCOM file consists of a header section, records, and a trailer section. Within these sections, records represent people (INDI record), families (FAM records), sources of information (SOUR records), and other miscellaneous records, including notes. Every line of a GEDCOM file begins with a level number where all top-level records (HEAD, TRLR, SUBN, and each INDI, FAM, OBJE, NOTE, REPO, SOUR, and SUBM) begin with a line with level 0, while other level numbers are positive integers.

Although it is theoretically possible to write a GEDCOM file by hand, the format was designed to be used with software and thus is not especially human-friendly. A GEDCOM validator[9] that can be used to validate the structure of a GEDCOM file is included as part of PhpGedView project, though it is not meant to be a standalone validator. For standalone validation you can use "The Windows GEDCOM Validator"[10] or the older unmaintained Gedcheck[11] from The Church of Jesus Christ of Latter-day Saints.

During 2001, The GEDCOM TestBook Project evaluated how well four popular genealogy programs conformed to the GEDCOM 5.5 standard using the Gedcheck program.[12] Findings showed that a number of problems existed and that "The most commonly found fault leading to data loss was the failure to read the NOTE tag at all the possible levels at which it may appear."[13] In 2005, the Genealogical Software Report Card was evaluated (by Bill Mumford who participated in the original GEDCOM Testbook Project)[14] and included testing the GEDCOM 5.5 standard using the Gedcheck program.[15]

Example[edit]

sample.ged
0 HEAD
1 SOUR Reunion
2 VERS V8.0
2 CORP Leister Productions
1 DEST Reunion
1 DATE 11 FEB 2006
1 FILE test
1 GEDC
2 VERS 5.5
1 CHAR MACINTOSH
0 @I1@ INDI
1 NAME Bob /Cox/
1 SEX M
1 FAMS @F1@
1 CHAN
2 DATE 11 FEB 2006
0 @I2@ INDI
1 NAME Joann /Para/
1 SEX F
1 FAMS @F1@
1 CHAN
2 DATE 11 FEB 2006
0 @I3@ INDI
1 NAME Bobby Jo /Cox/
1 SEX M
1 FAMC @F1@
1 CHAN
2 DATE 11 FEB 2006
0 @F1@ FAM
1 HUSB @I1@
1 WIFE @I2@
1 MARR
1 CHIL @I3@
0 TRLR

The following is a sample GEDCOM file. The first column indicates an indentation level.

The header (HEAD) includes the source program and version (Reunion, V8.0), the GEDCOM version (5.5), and the character encoding (MACINTOSH), which is invalid, as according to the GEDCOM 5.5 specification; valid choices are ANSEL, UNICODE or ASCII.

The individual records (INDI) define Bob Cox (ID 1—@I1@), Joann Para (ID 2), and Bobby Jo Cox (ID 3).

The family record (FAM) links the husband (HUSB), wife (WIFE), and child (CHIL) by their ID numbers.

Versions[edit]

The current version of the specification is GEDCOM 5.5, which was released on 12 January 1996. A subsequent draft GEDCOM 5.5.1[16] specification was issued in 1999, introducing nine new tags, including WWW, EMAIL and FACT, and adding UTF-8 as an approved character encoding. This draft has not been formally approved, but its provisions have been adopted in some part by a number of genealogy programs[17][18][19] and is used by FamilySearch.org[20] While PAF 5.2 does support GEDCOM 5.5, PAF 5.2 uses UTF-8 as its internal character set, a feature which was introduced in the GEDCOM 5.5.1 draft, and can output a UTF-8 GEDCOM.[21][22]

On 23 January 2002, a draft (beta) version of GEDCOM 6.0 was released for developer study only, as it was not a complete specification, and developers were recommended to not begin implementation in their software. For example, descriptions of the meaning and expected contents of tags were not included.[23] GEDCOM 6.0 was to be the first version to store data in XML format, and was to change the preferred character set from ANSEL to Unicode.

Lineage-linked GEDCOM is the deliberate de facto common denominator.[1] Despite version 5.5 of the GEDCOM standard first being published in 1996, many genealogical software suppliers have yet to support the feature of multilingual Unicode text (instead of the ANSEL character set) introduced with that version of the specification. Uniform use of Unicode would allow for the usage of international character sets. An example is the storage of East Asian names in their original Chinese, Japanese and Korean (CJK) characters, without which they could be ambiguous and of little use for genealogical or historical research.[21]

Release history[edit]

Meaning
Red Old Standard/Draft; not supported
Yellow Old Standard; still supported
Green Current Standard
Blue Future Draft
GEDCOM Version Release Date Notes
1.0[24] 1984[25] -
2.0[24] Dec 1985[26] PAF 2.0
2.1 Feb 1987[26] GEDCOM for PAF 2.1
2.3 Draft 7 August 1985[27] with PAF2.0 GEDCOM implementation conventions
2.4 Draft 13 December 1985[27] with PAF2.0 GEDCOM implementation conventions
3.0 Standard[24] 9 October 1987[28] PAF 2.0 and 2.1 implementation of 3.0
4.0 Standard August 1989 PAF 2.1 - 2.31
4.1 Draft[29] - -
4.2 Draft[30] 25 January 1990[31] -
5.0 Draft[24] 31 December 1991[27] lineage-linked structures were introduced.[32]
5.1 Draft 18 September 1992[26] -
5.2 Draft 22 January 1992[33] -
5.3 Draft 4 November 1993[34] Unicode standard (ISO/IEC 10646) was introduced as an additional character set.
5.4 Draft 21 August 1995[35] -
5.5 Standard 11 December 1995[36] PAF 3, 4 and 5
5.5 Standard + Errata Sheet 2 January 1996[37][38] PAF 3, 4 and 5
GEDCOM (Future Direction) Draft[32][39] 1 May 1998[40][41] "it used an entirely new data model"[42]
5.5.1 Draft[43][44] 2 October 1999[16] Used by FamilySearch.org[20] UTF-8 added as an approved character encoding.
5.6 Private Draft -[45] "Jed Allen sent those two files to a few people only for sort of "private comments"[46]
6.0 XML Draft 28 December 2001[47] Was not a complete specification, and not recommended to begin to software implementations.

Limitations[edit]

Support for multi-person events and sources[edit]

A GEDCOM file can contain information on events such as births, deaths, census records, ship's records, marriages, etc.; a general rule of thumb is that an event is something that took place at a specific time, at a specific place (even if the time & place are not known). GEDCOM files can also contain attributes such as physical description, occupation, and total number of children; unlike events, attributes generally cannot be associated with a specific time or place.

The GEDCOM specification requires that each event or attribute is associated with exactly one individual or family.[48] This causes redundancy for events such as census records where the actual census entry often contains information on multiple individuals. In the GEDCOM file, for census records a separate census "CENS" event must be added for each individual referenced. Some genealogy programs, such as GRAMPS and The Master Genealogist, have elaborate database structures for sources that are used, among other things, to represent multi-person events. When databases are exported from one of these programs to GEDCOM, these database structures cannot be represented in GEDCOM due to this limitation, with the result that the event or source information including all of the relevant citation reference information must be duplicated each place that it is used. This duplication makes it difficult for the user to maintain the information related to sources.

In the GEDCOM specification, events that are associated with a family such as marriage information is only stored in a GEDCOM once, as part of the family (FAM) record, and then both spouses are linked to that single family record.[48]

Ambiguity in the specification[edit]

The GEDCOM specification was made purposefully flexible to support many ways of encoding data, particularly in the area of sources. This flexibility has led to a great deal of ambiguity, and has produced the side effect that some genealogy programs which import GEDCOM do not import all of the data from a file.[49]

Support for varying definitions of families and relationships[edit]

GEDCOM does not explicitly support data representation of many types of close interpersonal relationships, such as same-sex marriages, domestic partnerships, cohabitation, polyamory, polygamy or incest, but such relationships and any other can be represented using the ASSO tag.

Ordering of events that do not have dates[edit]

The GEDCOM specification does not offer explicit support for keeping a known order of events. In particular, the order of relationships (FAMS) for a person and the order of the children within a relationship (FAM) can be lost. In many cases the sequence of events can be derived from the associated dates. But dates are not always known, in particular when dealing with data from centuries ago. For example, in the case that a person has had two relationships, both with unknown dates, but from descriptions it is known that the second one is indeed the second one. The order in which these FAMS are recorded in GEDCOM's INDI record will depend on the exporting program. In Aldfaer[50] for instance, the sequence depends on the ordering of the data by the user (alphabetical, chronological, reference, etc.). The proposed XML GEDCOM standard[47] does not address this issue either.

Lesser-known features[edit]

GEDCOM has many features that are not commonly used, and hence are unknown to some people. Some software packages do not support all the features that the GEDCOM standard allows.

Multimedia[edit]

The GEDCOM standard supports the inclusion of multimedia objects (for example, photos of individuals).[51] Such multimedia objects can be either included in the GEDCOM file itself (called the "embedded form") or in an external file where the name of the external file is specified in the GEDCOM file (called the "linked form"). Embedding multimedia directly in the GEDCOM file makes transmission of data easier, in that all of the information (including the multimedia data) is in one file, but the resulting file can be enormous. Linking multimedia keeps the size of the GEDCOM file under control, but then when transmitting the file, the multimedia objects must either be transmitted separately or archived together with the GEDCOM into one larger file. Support for embedding media directly was dropped in the draft 5.5.1 standard.[52]

Conflicting information[edit]

The GEDCOM standard allows for the specification of multiple opinions or conflicting data, simply by specifying multiple records of the same type. For example, if an individual's birth date was recorded as 10 January 1800 on the birth certificate, but 11 January 1800 on the death certificate, two BIRT records for that individual would be included, the first with the 10 January 1800 date and giving the birth certificate as the source, and the second with the 11 January 1800 date and giving the death certificate as the source. The preferred record is usually listed first.

This example encoded in GEDCOM might look like this:

0 @I1@ INDI
1 NAME John /Doe/
1 BIRT
2 DATE 10 JAN 1800
2 SOUR @S1@
3 DATA
4 TEXT Transcription from birth certificate would go here
3 NOTE This birth record is preferred because it comes from the birth certificate
3 QUAY 2
1 BIRT
2 DATE 11 JAN 1800
2 SOUR @S2@
3 DATA
4 TEXT Transcription from death certificate would go here
3 QUAY 2

Conflicting data may also be the result of user errors. The standard does not specify in any way that the contents must be consistent. A birth date like "10 APR 1819" might mistakenly have been recorded as "10 APR 1918" long after the person's death. The only way to reveal such inconsistencies is by rigorous validation of the content data.

Internationalization[edit]

The GEDCOM standard supports internationalization in several ways. First, newer versions of the standard allow data to be stored in Unicode (or, more recently, UTF-8), so text in any language can be stored.[53] Secondly, in the same way that you can have multiple events on a person, GEDCOM allows you to have multiple names for a person,[54] so names can be stored in multiple languages (although there is no standardized way to indicate which instance is in which language). Finally, in the latest draft version (5.5.1, not yet in widespread use), the NAME field also supports a phonetic variation (FONE) and a romanized variation (ROMN) of the name.[55]

GEDCOM X[edit]

In February 2012 at the RootsTech 2012 conference, FamilySearch outlined a major new project around genealogical standards called GEDCOM X, and invited collaboration. It will include software developed under the Apache open source license. It includes data formats that facilitate basing family trees on sources and records (both physical artifacts and digital artifacts), support for sharing and linking data online, and an API.[7][56][57]

Alternatives to GEDCOM[edit]

Commsoft, the authors of the Roots[58] series of genealogy software and Ultimate Family Tree, defined a version called Event-Oriented GEDCOM (also known as "Event GEDCOM" and originally called InterGED[59]),[60] which included events as first class (zero-level) items. Although it is event based, it is still a model built on assumed reality rather than evidence. Event GEDCOM was more flexible, as it allowed some separation between believed events and the participants. However, Event GEDCOM was not widely adopted by other developers due to its semantic differences.[citation needed] With Roots and Ultimate Family Tree no longer available, very few people today are using Event GEDCOM.[61]

GRAMPS XML is an XML-based open format created by the open source genealogy project GRAMPS and used also by PhpGedView.

See also[edit]

References[edit]

  1. ^ a b c Subject: GEDCOM and Formal Standards Organizations Date: Wed, 24 Jan 1996 11:53:52 -0700 From: Bill Harten - Organization: Brigham Young University "why wasn't GEDCOM developed through a formal standards organization?..."Thus GEDCOM was born as a deliberate, de facto standard, to be followed only by those who felt it was in their best interest to do so.
  2. ^ Subject: rep: T Jenkins - open letter to GEDCOM-L - "The goal was to try and provide a standard to allow developers to provide a vehicle for their users to share genealogical conclusions and supporting evidence with others." From: "Jed R. Allen" Brigham Young University - Date: 29 Sep 1995 17:40:04 -0600 - GEDCOM-L Archives -- September 1995, week 5 (#7)
  3. ^ "Genealogical Software Report Card". March 2005. 
  4. ^ GEDCOM 5.5 EL (Extended Locations) specification
  5. ^ Ability to save information against places - "Support for parts of the GEDCOM 5.5EL proposal" - FHUG Wish List
  6. ^ 0000688: Support for Gedcom 5.5EL - Gramps Bugtracker
  7. ^ a b "GEDCOM X". FamilySearch. Retrieved February 4, 2012. 
  8. ^ 2012-08-31 GEDCOM X: no industry standard, FamilySearch abandons GEDCOM X push, By Tamura Jones, Modern Software Experience.
  9. ^ View of phpgedview's GEDCOM validator source code
  10. ^ The Windows GEDCOM Validator (dead link)
  11. ^ Gedcheck - "uses a grammar file for the specific version of GEDCOM you want to check against." The Church of Jesus Christ of Latter-day Saints
  12. ^ "GEDCOM TestBook Project". 2001. 
  13. ^ [GEDCOM and the GenTech Testbook Project] Genealogical Computing 7/1/2001 - Archive Summer 2001 Vol. 21.1 - Ancestry.com
  14. ^ The Genealogical Software Report Card 2000 S W Mumford Last updated March 2005[unreliable source?]
  15. ^ Reviews from the NGS Newsmagazine and its Predecessors. - Test Result are in the PDF's
  16. ^ a b GEDCOM 5.5.1 draft
  17. ^ GED-GEN is based on GEDCOM version 5.5.1 (draft), dated 2 October 1999. The following record types are parsed: header, individual, family, notes, source, and repository. However not all elements within these records are processed. - Specifications - GED-GEN Introduction
  18. ^ 0000688: Support for Gedcom 5.5EL(0008068) romjerome (developer) 2009-01-25 06:13 - "Note : GRAMPS 3.0.x supports a part of GEDCOM 5.5.1 on export, which is not supported by most programs" - Gramps Bugtracker
  19. ^ "MyBlood supports the GEDCOM 5.5 and 5.5.1 file format." - MyBlood Support - Forum, FAQ, Know Problems
  20. ^ a b FamilySearchtoGEDCOMMapping.doc - FamilySearch XML to GEDCOM Mapping - .."The GEDCOM v5.5.1 (http://www.phpgedview.net/ged551-5.pdf) specification was used as the target for the GEDCOM side."
  21. ^ a b Personal Ancestral File 5.2 and PAF Companion 5.4 - Software Version Changes Release 5.0.1.4, 22 December 2000 - "10.GEDCOM improvements: Table:Destination:PAF 5 GEDCOM Version:5.5 Character Set:UTF-8
  22. ^ Personal Ancestral File 5.1 - "Also noted in a second test was the use of four tags from a later draft version of the Gedcom specification, FONE (phonetic name), ROMN (romanized name), EMAIL (e-mail), and _UID" Jan/Feb 2002 NGS Newsmagazine
  23. ^ GEDCOM 6.0 specification
  24. ^ a b c d pafuser : Beitrag: Re: [pafuser] PAF 5.01 und GEDCOM By Eckhard Henkel - Beitrag #103 von 1494 - Yahoo Groups
  25. ^ Subject:description of InterGED theory From:Gary Steiner - "The first GEDCOM standard, version 1.0, was released to the genealogical software development community in 1984." - GEDCOM-L Archives -- July 1994, week 4 (#14)
  26. ^ a b c Subject:Timeline of GEDCOM versions and PAF By George Archer - GEDCOM-L Archives -- November 2000, week 3 (#12)
  27. ^ a b c Subject:Re: GEDCOM standards help please From:Graham Starkey - "DRAFT VERSION 2.3–7 August 1985 with PAF2.0 GEDCOM implementation conventions" - GEDCOM-L Archives -- June 2000, week 4 (#1)
  28. ^ RootsWeb: ROOTS-L Re: Large Charts (fairly long):Date:Tue, 11 Jul 89 15:14:31 CDT From: Marty Hoag <NU021172@N...> Subject:Re: Printing trees with PAF? From soc.roots ... * GEDCOM release 3.0, 9 Oct 1987, 131 pages (!)
  29. ^ This GEDCOM format uses the 4.1 GEDCOM specification
  30. ^ File Structures for PAF and GEDCOM - Date: 1996/01/04 - soc.genealogy.computing | Google Groups:
  31. ^ Subject:4.x specs From:Rafal Prinke -"while this document has the date January 25, 1990. So maybe it is GEDCOM 4.2 ?" - GEDCOM-L Archives -- May 1994, week 1 (#19)
  32. ^ a b Subject: GEDCOM (Future Direction) Announced by Family History From: "Jed R. Allen" Date: Fri, 1 May 1998 18:08:24 -0600
  33. ^ Subject:Re: GEDCOM standards help please From:Graham Starkey - "DRAFT Release 5.2–22 January 1992 120kb" - GEDCOM-L Archives -- June 2000, week 4 (#1)
  34. ^ GEDCOM 5.3 draft - 4 November 1993
  35. ^ THE GEDCOM STANDARD - DRAFT Release 5.4–21 August 1995
  36. ^ Subject:Timeline of GEDCOM versions and PAF By George Archer - "5.5 11 Dec 1995 (Title Page for 5.5)"- GEDCOM-L Archives -- November 2000, week 3 (#12)
  37. ^ GEDCOM 5.5 Standard (Executable file in Envoy format)
  38. ^ Re: Looking for GEDCOM versions 4 & 5.xx "Brian C. Madsen" - "A GEDCOM 5.5 Errata Sheet dated 10 January 1996 supposedly contains corrections to pages 23, 24, 25, 26, 29, 29, 29, 33, 34, 39, 57, 79, and 85."
  39. ^ GEDCOM Specification Future Direction (1999-07-07)
  40. ^ "According to the Family History Department's Jed Allen who sent out the announcement message, the GEDCOM (FD)"
  41. ^ Comments on the GEDCOM Future Directions document Michael H. Kay, 17 May 1998
  42. ^ Subject:GEDCOM Future Directions - From:John Nairn - Date:Mon, 11 May 1998 13:38:45 -0600 - GEDCOM-L Archives -- May 1998, week 2 (#3)
  43. ^ GEDCOM 5.51 data model in UML format - Software Renovation Corporation
  44. ^ Modifications in Gedcom Version 5.5.1 compared to Gedcom 5.5
  45. ^ Subject:Re: GEDCOM History From:STEFANO BOSCOLO - Date:Tue, 20 Feb 2001 19:54:06 +0100 - GEDCOM-L Archives -- February 2001, week 3 (#1)
  46. ^ Subject: Re: GEDCOM History From:"Rafal T. Prinke" - Date:Tue, 20 Feb 2001 22:14:55 +0100 - GEDCOM-L Archives -- February 2001, week 3 (#4)
  47. ^ a b Draft Specification for GEDCOM XML 6.0
  48. ^ a b GEDCOM Standard 5.5, pp. 26-27.
  49. ^ "Why GEDCOM Files are Not in Sync with All Genealogy Programs". 2011-04-24. 
  50. ^ http://www.aldfaer.nl
  51. ^ GEDCOM Standard 5.5, p. 28.
  52. ^ Draft GEDCOM Standard 5.5.1, p. 6.
  53. ^ GEDCOM Standard 5.5, p. 45.
  54. ^ GEDCOM Standard 5.5, p. 27.
  55. ^ GEDCOM Draft 5.5.1, p. 38
  56. ^ "Ryan Heaton: A New GEDCOM". The Ancestry Insider. 2012-02-04. Retrieved 2012-02-16. 
  57. ^ "RootsTech Learning #3 - GEDCOM X and/or BetterGEDCOM and/or FHISO". Stardust 'n' Roots. 2012-02-13. Retrieved 2012-02-16. 
  58. ^ CommSoft to Return? Dick Eastman Online 3/14/2001 - Archive - Ancestry.com
  59. ^ RootsWeb: TMG-L [TMG] InterGED/Event GEDCOM Date: Fri, 15 Feb 2002 13:33:18 -0700
  60. ^ "Commsoft : The Roots Story". Retrieved 2008-11-20. 
  61. ^ "TMGL Archives : Event-oriented". 2000-06-29. Retrieved 2008-11-20. 

External links[edit]

General
Commentary