gedcom-occurrences

Version: 0.2.0

⚠️ Breaking Change in v0.2.0: This extension now uses a container-only model. See MIGRATION_GUIDE.md for upgrade instructions.

This repository contains proposed FamilySearch GEDCOM extensions for representing independent events that involve multiple participants with specific roles.

This extension enables GEDCOM 7 to handle shared events (like census enumerations, group burials, ceremonies) without duplicating event data across multiple person records.

Quick Example

Traditional GEDCOM duplicates shared events:

0 @I1@ INDI
1 NAME John /Smith/
1 CENS
2 DATE 1850
2 PLAC Boston

0 @I2@ INDI  
1 NAME Mary /Smith/
1 CENS
2 DATE 1850
2 PLAC Boston

With the Occurrence Extension (hybrid compatibility):

0 HEAD
1 SCHMA
2 TAG _OCUR https://gedcom.io/terms/v7/_OCUR
2 TAG _PART https://gedcom.io/terms/v7/_PART
2 TAG _OCREF https://gedcom.io/terms/v7/_OCREF

0 @O1@ _OCUR              # Shared occurrence (event data only)
1 TYPE Census
1 DATE 1850
1 PLAC Boston
1 _PART @I1@             # Simple reference
1 _PART @I2@             # Simple reference

0 @I1@ INDI
1 NAME John /Smith/
1 _OCREF @O1@            # Reference to shared occurrence
2 ROLE Head              # Participant data here
2 AGE 45y                # Participant data here
1 CENS                   # For backward compatibility
2 DATE 1850
2 PLAC Boston

0 @I2@ INDI
1 NAME Mary /Smith/
1 _OCREF @O1@            # Reference to shared occurrence  
2 ROLE Spouse            # Participant data here
2 AGE 42y                # Participant data here
1 CENS                   # For backward compatibility
2 DATE 1850
2 PLAC Boston

Extensions

The following extension is proposed for discussion:

• Occurrence Extension

All proposed extensions use documented extension tags. If they later become incorporated into the FamilySearch GEDCOM standard, standard tags will be defined at that time.

Rather than write out URIs in full, we use prefix notation: any URI beginning with one of the following short prefixes followed by a colon is shorthand for a URI beginning with the corresponding URI prefix

Short Prefix	URI Prefix
g7	https://gedcom.io/terms/v7/
ext	https://github.com/glamberson/gedcom-occurrences/

Tags Provided

• _OCUR - Occurrence record (independent event with multiple participants)
• _PART - Participant in an occurrence (specifies person and role)
• _OCREF - Occurrence reference (links person to occurrence)

Benefits

1. Single Source of Truth: Event data stored once, referenced multiple times
2. Rich Participation: Multiple people with specific roles
3. Research Clarity: Models complex historical events accurately
4. Tool Compatibility: Maps cleanly to GRAMPS and GEDCOM X event models
5. Backward Compatibility: Can coexist with traditional embedded events

Status

Published - v0.2.0 released

Registry Submission - Submitted to GEDCOM Registry PR #173

See Also

• Specification
• Glossary
• Compatibility Guide
• Examples
• YAML Definitions
• Registry-Compliant YAML