STEMMA History

Development of the STEMMA® ("Source Text for Event and Ménage MApping”) data model and source format began around 2011. This page charts its chronological history.

Draft [2012-01-02]

First draft specification uploaded to new STEMMA Web site.

Draft [2012-04-27]

The STEMMA research notes were collected together and made (almost) readable. The 70+ pages were uploaded to the STEMMA site as a resource for any similar work on family history data to utilise.

V1.0 [2012-07-16]

STEMMA passed from being a draft specification to the first fully working version.

A number of its features were streamlined or revised as a result of it being applied to my own data, and following further research. The copious associated Research Notes were updated in keeping with the new specification, and supplemented by a Data Model section that shows the model being applied to a number of case studies.

New or improved features include:

• Rationalised way of extending partially controlled vocabularies in order to support custom types, subtypes, roles, styles, and other tag values.
• Unified approach to defining core and custom properties for Persons and Places.
• Streamlined handling of multi-valued properties (and of Citation/Resource parameters) such as 'Roles'.
• Support for local-events (i.e. that only affect one person).
• Support for Events with multiple sources of information, i.e. multiple sets of properties for each associated Person.
• Support for Dublin Core semantic tags for both Person/Place properties and Resource/Citation parameters. Support for their machine-readable OpenURLs.
• Streamlined approach to Person and Place names that retains their unified handling but accommodates name types, name styles and sorting for different cultures.
• Support for Dual Dates (aka Double Years).
• Support for URL hyperlinks in narrative.
• Support for general reference notes in narrative.
• Copyright and other permissions/prohibitions.
• Identification of physical artefacts as Resources.
• Extended inheritance mechanism to Resources (e.g. attachments) and Citations (e.g. sources) so that the same details may be shared between multiple entities.

V2.0 [2013-05-28]

STEMMA underwent a considerable number of refinements to both strengthen and streamline its specification. Features include:

• Better support for recording transcriptions, including uncertain characters, marginalia, original emphasis, alternative spellings/meanings.
• Better separation of evidence from conclusion for marked-up references and for Property values.
• Generic Group concept that can be used to model time-dependent Sets of Person, e.g. family units.
• Support for attribution of individuals, whether represented within the family history or external to it. Contact details, including address, phone, email addresses, Web sites, and messaging systems.
• Revised date-string representation for world calendars.
• Downloads section added to Web site.

V2.1 [2013-10-16]

Changes include:

• Changes to NoteRef. Added new Anom element for transcription anomalies.
• Allow <br> in orig-text data.
• Added Hamlet place-type.

V2.2 [2014-04-17]

Changes include:

• Changed Group to also represent real-life entity rather than just Person Sets. Include hierarchy, events, alternative names, subtype, resources (docs & photos).
• Added GroupRef mark-up.
• Added GroupRef data-type.
• Move Person GroupLnk inside EventLnk/Eventlet.
• Split BirthEvent/DeathEvent to allow for Eventlet.
• Have equivalent to Birth/Death (Creation & Demise) for Group and Place. Replaces Void in Places.
• Handle "related entities" with JoinFrom (in Creation), SplitTo (in Demise), and RelatedTo elements in Place/Group.
• Simplify Eventlet by removing hierarchy support.
• Persisted Counters in Dataset header for assisted key generation.
• Added GroupProperties to ExtendedProperties.
• Event Place optional in Eventlet.
• Resource entity distinguishes physical artefacts and images thereof.
• Improved digital data-types for Resources.
• Sensitivity levels accepted on Resources (e.g. photographs and documents).
• External IDs accepted on Person, Place, Group, and Event entities.

V3.0 [2014-10-20]

Major change to trim excess flexibility, and to address certain known failings:

• Could not represent the Properties for unidentified or incidental people in a given source.
• Overloading of Role Property with relationships.
• Problems representing a “directed Property”, to another entity reference, as opposed to, say, Head.Wife.
• Cannot inherit from an Event when it has Detail elements in it.
• Representation of top-level research reports.

Changes include:

• Reversal of Person-to-Event (etc) links to place Properties in the Event, alongside the respective source details.
• Added References element to Event for representing subject references in the sources, and their respective Properties. This element supersedes the previous Detail element.
• Introduction of “abstract” entities for the sole purposes of inheritance.
• Make Event hierarchies bottom-up rather than top-down for consistency and ease of validation.
• Deprecation of parameter substitution into Citation URIs; both named parameter markers and the ‘=?’ form.
• Inclusion of NARRATIVE as a top-level Dataset entity for research reports and authored works.
• Changed semantic types on Properties and Parameters to use “DC:” namespace prefix rather than simply “DC.”. DCType attribute changed to SemType.
• Reinstatement of Event-specific Property values to represent named items of information for an event.
• Explicit control over entity-Key imports for multi-Dataset Documents and multi-Document collections.
• PersonEL, PlaceEL, and GroupEL data-types added for Properties that describe a relationship between two evidential subjects, such as person-to-person.
• Addition of ‘Header’ TEXT_TYPE for details of authorship, title, etc., in narrative works.
• Adjustments to NAME_VARIANTS to move the Type attribute, add an Initial=’boolean’ option for using initials, an indication of cultural style, and an optional override for character sorting.
• Added optional PersonalName (within Person entity) to complement PlaceName (in Place) and GroupName (in Group).
• Revise syntax of <Constraints> element to associate narrative with a specific constraint, e.g. to express causal relationships.
• Added optional coordinates to a Place in order to represent a point, an enclosed area (i.e. polygon), or an open line (e.g. for a street).
• Separation of Relationship from Role.
• Several new event-types and event-subtypes.

V4.0 [2015-11-22]

Major change to finally accommodate sources, information, evidence, and conclusions in a single model that supports the major approaches to research and representation.

Changes include:

• Introduction of a new Source entity that embraces both Citations and Resources for a particular information source. Citations and Resource entities are now connected to Source entity rather than to each other.
• Support for source assimilation & analysis, source mining, and the ability to drill-down on conclusions, all provided via the Source entity.
• The <References> element, within Events, is now superseded by <SourceLnk> which links to the new Source entity. Enclosed *Ref elements (e.g. <PersonRef>) changed to *Lnk elements for consistency. Removal of the ID attribute introduced in V3.0.
• Support for cross-source analysis and correlation via a new Matrix entity.
• Support for a generalised approach to multi-tier personae.
• Additional of Animal entity, strongly modelled on Person entity, including related mark-up and namespaces.
• <CitationLnk>/<ResourceLnk> from Person, Place, Group, and Event entities, changed to <SourceLnk>.
• Reviewed the goal of sticking to XHTML tags for presentation, replacement of the <Hi> element with HTML-like ones, and the addition of support for <sup>/<sub> elements, columnar text, simple tables, and indentation.
• Removal of ‘Unreadable’ mode from the <Anom> element.
• Support for distinguishing manuscript and typescript transcriptions in the <Text> element. Support for numbering lines and pages in transcriptions. Positional control over annotations such as marginalia.
• <FromText> element added to <Narrative> in order to share re-usable sections of text. This has meant that the NoteKey attribute, in the semantic mark-up, was no longer required and so was deleted.
• Categorisation of the layers in a Citation chain.
• The optional <DisplayFormat> element of the Citation entity has been re-interpreted as a set of pre-formatted language-specific strings. This may exist in addition to the mandatory set of named parameter values, and the two together can also be used as a simple citation-template.
• The Intrinsic Functions, mentioned at the end of Semantic Mark-up, have been changed to Intrinsic Methods in preparation for defining a run-time object model. The set is also supplemented by ones for accessing subject-entity names.
• Small changes to subject-entity *-name-mode vocabularies to factor-out a generic name-mode (missing from previous specification).
• Place coordinates (including bounding shapes) are now time-dependent, the same as any parent-Place link.
• Added Canton and Colony to place-type vocabulary. The place-type of House is now replaced by Number and Apartment for flexibility.
• <Quality>, <Reliability>, and <Credibility> elements moved from the Citation entity to the new Source entity.

Although refinements will continue, I anticipate this to be the last major change to the STEMMA specification. I will, therefore, concentrate subsequent efforts on describing its advantages and philosophy, and in providing more worked examples.

V4.1 [2017-04-19]

Refinements to STEMMA specification, especially in the areas of transcription (multiple contributors, audio, and linking to images or recordings) and narrative mark-up (tabulated data, and citations).

Employment of the revised narrative support may be viewed in the fully-worked examples at: parallaxview.co/stemma/Resources/JessonLesson.xml and parallaxview.co/stemma/Resources/MoreOnGeorgeHearson.xml.

• ‘WhereIn’ attribute added to Citation Parameter definitions. This finally provides the missing criteria necessary for the automatic generation of shortened subsequent reference-note citations. ‘Subst’ attribute added to Citation parameter values in order to override formatting, or provide a substitution for cases on of a value being unavailable.
• <ParentCitationLnk> now allowed in both <CitationLnk> and <CitationRef> elements in order to create transient chained citations.
• Quality element, within Source entity, moved inside the Frame element.
• Review of entries in citation-layer-type namespace.
• DataControl element of Resource entity supports attribution text.
• Control of table widths, and individual column widths and alignments.
• Ability to align images when embedded within narrative.
• Ability to hyperlink images embedded in narrative.
• Requirement for enclosing Narrative element dropped for Text elements, except for top-level Narrative entities. Text elements can now be nested.
• <cb> replaced with <col>, and relationship between paragraphs and columns now reversed (paragraphs now within columns).
• ResourceRef Mode=SynchImage allows synchronisation between images and transcriptions.
• Corresponding SVG-x/y coordinates added to elements <page>, <col>, <p>, and <line>. Additional <posn> element defined to associate coordinates with arbitrary text locations.
• <Page>/<Line> renamed to <page>/><line> and moved alongside <p>/<col> as related to structure and content rather than semantics.
• Mode=Tablenote attribute supplementing Foonote and Endnote in various places.
• Text-element Header=boolean attribute replaced with Class=Header | H1 | H2 | H3 | Caption | Footnote | Endnote | Legend | Tablenote.
• Text-element Class=Caption attribute used in Resource/ResourceRef and tables for generating captions.
• Text-element Class=Footnote | Endnote | Tablenote attribute used in CitationRef to allow pre-formed (preferred) citations.
• Deprecated the <Text> attributes Abstract=boolean, Extract=boolean, Manuscript=boolean, and Transcript=boolean..<voice> mark-up added to supplement existing <ts>/<ms> mark-up. <ts>/<ms>/<voice> all enhanced to cope with different hands, voices, fonts, colours, etc.
• In transcripts of audio recordings, support for multiple voices, overlapping dialogue, intonation, gestures, noises, pauses, timestamps, etc.
• ResourceRef Mode=SynchAudio allows synchronisation between audio recordings and transcriptions, analogous to SynchImage for textual transcription (above).
• Complete revision of Mode values for CitationRef element.
• Relaxation of Date Parameters in order to cover the full range of calendars. One requirement was to represent the date-of-issue for newspaper sources that predated the Julian-to-Gregorian changeover.

V4.1 still [2020-12-10]

Canonical URL changed to https://parallaxview.co/stemma following a move from Google Sites to neocities.org. The previous URLs (http://www.familyhistorydata.parallaxview.co, http://stemma.parallaxview.co, and http://www.parallaxview.co/familyhistorydata) will be redirected to the new URL.

V4.1 still [2024-01-01]

At the end of 2020, the public version of the STEMMA specification was fixed at V4.1, although a number of small changes in specification and direction have occurred internally for private usage. Little work has taken place on the informational sub-model that was to support a dynamic research process, but a spin-off of the associated experimentation was the SVG Family-Tree Generator (SVG-FTG) that is now a separate product. Work has focused, instead, on the conclusional sub-model (see STEMMA Latest). Since that time, GEDCOM v7.0 has been defined, but STEMMA remains in a niche of its own.