GEDCOM Evidence Extension

A GEDCOM 7-compliant extension for evidence-based genealogy, supporting the Genealogical Proof Standard (GPS) through dual patterns that work within GEDCOM's structural constraints.

Version

0.2.0 - Complete redesign for GEDCOM 7 compliance

Overview

This extension provides two complementary patterns for handling evidence in genealogical research:

1. Shadow Records Pattern - Floating evidence that can be referenced by multiple individuals
2. Event Container Pattern - Evidence attached directly to specific individuals

Both patterns work within GEDCOM 7's rules while supporting evidence-first research methodologies.

Key Features

• GEDCOM 7 Compliant - Follows all pointer, record, and substructure rules
• Evidence Containers - Store source information exactly as found
• Flexible References - Individuals can reference shared evidence
• Confidence Assessment - Track your confidence in evidence connections
• GPS Support - Aligns with professional genealogical standards

Why This Redesign?

Version 0.1.x attempted polymorphic pointers and bidirectional references that violate core GEDCOM rules. Version 0.2.0 works WITH GEDCOM's constraints for a cleaner, compliant design.

Installation

1. GEDCOM 7-compatible software should automatically recognize these extension tags
2. The YAML files follow the official GEDCOM registry format
3. All structures are designed to integrate seamlessly with standard GEDCOM

The Two Patterns

Pattern 1: Shadow Records (Floating Evidence)

Use this when evidence might apply to multiple people or when identity is uncertain.

0 @E1@ _EVID
1 _DTYPE Census
1 DATE 7 JUN 1850
1 SOUR @S1@
2 PAGE Lines 15-16
1 _FIND John Smith, age 42, farmer
2 TYPE Personal Information
1 _FIND Mary Smith, age 38
2 TYPE Spouse Information

0 @I1@ INDI
1 NAME John /Smith/
1 _EVREF @E1@
2 _CONF High
2 _USED Name and age match other records

0 @I99@ INDI
1 NAME John /Smith/
1 _EVREF @E1@
2 _CONF Low
2 _USED Age differs by 5 years

Pattern 2: Event Container (Attached Evidence)

Use this when evidence definitively belongs to a specific person.

0 @I1@ INDI
1 NAME Sarah /Jones/
1 _EVEN_EVID
2 TYPE Evidence Discovery
2 DATE 15 MAR 2024
2 SOUR @S5@
3 PAGE Image 1234
2 _FIND Sarah Jones born 4 May 1823
3 TYPE Birth Information
2 _CONF High

Extension Structures

• _EVID - Evidence Container Record (level 0)
• _EVREF - Evidence Reference (points from person to evidence)
• _FIND - Specific finding within evidence
• _EVEN_EVID - Evidence as an event
• _CONF - Confidence level (High/Medium/Low/Hypothesis)
• _USED - How evidence was used
• _DTYPE - Document type
• _ANAL - Analysis notes

Key Benefits

1. Preserves Original Evidence - Never lose what sources actually said
2. Supports Uncertain Identity - Evidence can exist independently
3. GEDCOM Compliant - Works within all structural rules
4. GPS Aligned - Supports professional research standards
5. Flexible Application - Use one or both patterns as needed

Documentation

• RULES_AND_CONSTRAINTS.md - What is and isn't allowed
• Design Rationale - Why these design choices
• Migration Guide - Upgrading from v0.1.x
• Use Cases - Real-world examples
• Examples - Sample GEDCOM files

Community Foundation

This extension builds on 15 years of community discussion, particularly:

• BetterGEDCOM project insights (2010-2013)
• GEDCOM 7 development feedback
• Professional genealogist requirements

Status

Version 0.2.0 - Complete redesign addressing fundamental GEDCOM compliance issues

Previous PR - v0.1.x PR #178 was closed due to rule violations

Next Steps - New PR to be submitted with compliant design

Contributing

This extension is open for community input. Please see CONTRIBUTING.md for guidelines.

License

Released under the same terms as GEDCOM 7 specifications.