Glossary
This page collects the formal terms used by the Extended Matrix language. Each entry points back to the main chapter that defines the concept in detail; this glossary is meant as a quick-lookup reference, not as a substitute for the chapters themselves.
Note
Editors: keep entries short (1–3 sentences). The canonical definition lives in the linked chapter — this page only restates the gist and points there.
- 3DSC
3D Survey Collection — the open-source Blender add-on (with a companion Metashape pipeline) for managing photogrammetric and 3D survey data: level-of-detail handling, texture baking, and asset preparation ready to be linked to an EM graph. Part of the Extended Matrix Framework (EMF). See the 3DSC documentation.
- Activity
An Activity Node Group — a set of stratigraphic units linked by a common operation (e.g. “construction of the apse”). See Activity Nodes Group.
- Canvas
The yEd surface where the EM graph is authored. Carries the metadata used by the framework — site code, epoch palette, author, licence — typically inside an
SL_PDnodegroup, and organises nodes by Epoch through swimlanes. See Canvas.- Combiner
A paradata node that combines multiple extractor outputs into a single Property (Qualia) value, typically when a single value cannot be derived from a single source. See Paradata Nodes Group.
- Document
A primary source — a survey drawing, a photograph, a manuscript, a publication — referenced by an Extractor to derive a Property (Qualia). See Document Nodes: Managing Archaeological Sources.
- EM graph
The visual notation of an Extended Matrix — the typed nodes and arcs as drawn on paper, in yEd with the yEd palette, or produced by AI-extraction workflows. The human-readable face of EM. Distinct from the in-memory S3D Graph that s3Dgraphy builds from it.
- EM Tools for Blender
- EM Tools
The open-source Blender add-on that connects an EM graph to 3D content inside Blender — browse stratigraphic units, link proxies, drive visualisation by epoch and property, export to Heriverse and CSV. Part of the Extended Matrix Framework (EMF). See the EM Tools manual.
- Epoch
A named time horizon used to attribute and filter stratigraphic units (
has_first_epoch/has_last_epoch). It is the temporal counterpart of a swimlane in the Canvas — every node that belongs to that period is contained within its swimlane, which acts as the visual home of the epoch in the EM graph. Epochs are not stratigraphic units themselves; they are the calendar against which units are placed. See Canvas.- Extended Matrix (EM)
- EM
The formal language for documenting stratigraphy and virtual reconstruction processes in cultural heritage. Defined as a typed visual notation drawable in yEd or producible programmatically via s3Dgraphy. See A stratigraphic approach.
- Extended Matrix Ecosystem
The combined whole of the formal language and its toolset: EM (the language) together with the Extended Matrix Framework (EMF) (the open-source toolset that operationalises it — yEd palette, EM Tools for Blender, s3Dgraphy, Heriverse, 3DSC). Used when you need to refer to the entire EM-aware stack as a single thing.
- Extended Matrix Framework (EMF)
The set of open-source software tools that operationalise the EM language: the yEd palette, EM Tools for Blender, 3DSC, Heriverse and the s3Dgraphy library that holds them together. See the framework overview.
- Extractor
A paradata node representing the act of extraction of an attribute from a Document. Materialises the “from-source-to-property” reasoning step. See Extractor Types.
- Heriverse
The web-based publication platform of the EM Framework — turns EM graphs and 3D content into navigable, paradata-aware online experiences. The public product name; the underlying conceptual model is StratiVerse (used in academic papers and internal manuals). See the Heriverse documentation.
- Knowledge Graph
The underlying property graph encoded by an EM graph, made programmatically accessible via s3Dgraphy as an S3D Graph. See The Knowledge Tree.
- Paradata
The reasoning that connects sources to interpretive results: what was used, how it was used, and what was concluded. Mandatory in EM — every reconstructive node must be backed by a paradata chain. See Paradata Nodes.
- Property (Qualia)
A typed paradata attribute attached to a stratigraphic unit — a measurable or qualitative value (length, material, dating, construction technique). Connected upstream to the Extractor and Combiner nodes that justify the value. See Properties (Qualia) and Paradata Nodes.
- pyArchInit
An open-source QGIS plugin for archaeological data management, with particular strength in 2D GIS visualization of stratigraphic data. Maintained by an active community led by Luca Mandolesi. In the Extended Matrix ecosystem, pyArchInit projects are consumed through the s3Dgraphy library, either by reference or by baking their records into the EM graph. See the PyArchInit ↔ Extended Matrix integration recipe for the integration workflow and the Ecosystem registry entry.
- S3D Graph
The in-memory property graph produced by s3Dgraphy. It is the runtime data structure with all methods for reading, writing and querying stratigraphic relationships, and is serialisable to JSON. Distinct from the visual notation (EM graph) which is the human-readable face — the S3D Graph is the machine-processable face of the same knowledge.
- s3Dgraphy
The open-source Python library that handles the mapping between tool-specific data formats (GraphML, JSON, XLSX) and the Stratigraphic Knowledge Graph. It is the package — the runtime artifact it produces is the S3D Graph. Used by every framework component (EM Tools for Blender, Heriverse, 3DSC) for any programmatic access to EM data. See the index page of this manual.
See also: a long-term perspective for this work, if it grows into a formalisation of CIDOC-CRM for 3D stratigraphy and virtual reconstruction, is the working name CRM-s3D (not currently in use; mentioned here for forward reference only).
- Special Find (SF)
A discrete object found in a stratigraphic unit, recorded as a separate entity (e.g. an inscription, a coin). See Auxiliary Stratigraphic nodes.
- Stratigraphic Unit (US)
The basic unit of archaeological stratigraphy: a discrete physical entity (a layer, a wall, a cut) recorded during excavation. EM extends this with virtual variants — see Stratigraphic Nodes.
- StratiVerse
The conceptual model that underlies the Heriverse product. Referenced in academic papers and internal manuals; the public tool name is Heriverse.
- Transformation Stratigraphic Unit (TSU)
A node type introduced in EM 1.4 (and refined in 1.5) for documenting states and transformations — decay, restoration, thematic surveys — rather than the original construction events.
- USD
A Documented Stratigraphic Unit — a unit attested by bibliographic, archival or iconographic documentation rather than by direct excavation. See Stratigraphic Nodes.
- USVn
A Virtual Stratigraphic Unit defined purely by typology — no in-situ anchor, the unit is reconstructed from comparanda and type-based reasoning. See Stratigraphic Nodes.
- USVs
A Virtual Stratigraphic Unit anchored to an in-situ archaeological remain. The anchor connects the inference back to tangible evidence. See Stratigraphic Nodes.
- Virtual Special Find (VSF)
A nodegroup containing SF fragments that have been reconstructed virtually. The VSF is a container, not a single reconstructed object. See Auxiliary Stratigraphic nodes.
- Virtual Stratigraphic Unit (USV)
A stratigraphic unit whose physical evidence is partial or absent and whose existence is inferred. Comes in two flavours — USVs (with an in-situ anchor) and USVn (pure typology). See Stratigraphic Nodes.
- yEd palette
The palette of EM-typed nodes and arcs that turns yEd (a free graph editor) into an EM graph authoring tool. The starting point for anyone drawing an EM by hand. Part of the Extended Matrix Framework (EMF).
Note
Editors: when you add a new term, place its short definition here and link to the chapter where the full discussion lives. Avoid redefining concepts in two places — the chapter is authoritative; the glossary entry is the lookup.