Date: 2026-04-21 Status: Canonical / cross-reference catalog Scope: Enumerate the named projections across Graphshell domain pairs. Reveals which domain-pair bridges are formally named, which are implicit, and where new projections (e.g., Graph Cartography) slot in.

Related:

• ../../TERMINOLOGY.md#projection-concepts — umbrella definition, three-form convention, mechanism terms
• unified_view_model.md — five-domain model (Shell / Graph / Navigator / Workbench / Viewer)
• graph_tree_spec.md — ProjectionLens as Shape-stage mechanism for tree-family projections
• ../implementation_strategy/navigator/navigator_projection_spec.md — Navigator projection pipeline
• ../implementation_strategy/subsystem_history/2026-04-21_graph_runtime_projection_layer_plan.md — Graph Cartography layer
• ../implementation_strategy/subsystem_history/2026-04-17_graph_memory_architecture_note.md — substrate and downstream projection layers

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A projection bridges a source (a domain's truth or substrate) with a target (a representation consumed by a different domain or surface). The three-form convention from TERMINOLOGY.md applies: a projection is the pattern, a projected view is the outcome, projecting is the process.

This document enumerates projections that exist or are planned, flags structurally-projections-but-not-currently-named ones, and lists open gaps where a domain pair has no contract yet.

Scope note: routing and mutation paths (e.g., Navigator → Graph via intents) are not projections — a projection is a read/derivation, not a mutation route. Routing contracts are cataloged elsewhere.

Target	Projection	Canonical doc	Status
Navigator	Navigator projection (all Navigator sections and graphlet derivations — pattern)	NAVIGATOR.md, navigator_projection_spec.md, archived navigator producing plan	Live; canonical pipeline spec landed
Workbench	Projection Rule (nodes→tiles, graphlets→tile groups, frames→frames — correspondence)	TERMINOLOGY.md Tile Tree Architecture §Projection Rule; workbench/2026-03-20_arrangement_graph_projection_plan.md	Live; graph-tree migration active
Viewer	Viewer resolution (AddressKind + ContentKind + mime_hint → viewer backend — backend selection)	viewer/viewer_presentation_and_fallback_spec.md; ViewerRegistry contract	Live; not previously named as a projection — flagged here for consistency
Graph canvas (rendered surface)	Canvas rendering (graph truth → spatial/visual rendering at current LOD)	graph/graph_canvas_spec.md; graph/graph_node_edge_interaction_spec.md	Live; not previously named as a projection
Workbench (secondary)	ArrangementRelation projection (arrangement edges → tile group / frame membership)	workbench/2026-03-20_arrangement_graph_projection_plan.md	Active migration

Target	Projection	Canonical doc	Status
Graph-memory consumers	Branch projection (substrate → owner-scoped current path + alternate children)	subsystem_history/2026-04-17_graph_memory_architecture_note.md §3.5	Live (branch_projection())
Graph-memory consumers	AggregatedEntryEdgeView (substrate visit parentage → entry-level multi-graph)	subsystem_history/2026-04-17_graph_memory_architecture_note.md §3.5	Live
Graph-memory consumers	Semantic summary (substrate → current URL, last-visit time, visit count)	subsystem_history/2026-04-17_graph_memory_architecture_note.md §6	Live (semantic_summary())
Linear-history consumers	Linear projection (substrate → flat linear navigation history)	subsystem_history/2026-04-17_graph_memory_architecture_note.md §6	Live (projection())
VGCP wire format	Contribution projection (live memory → canonicalized signed shareable artifacts)	subsystem_history/2026-04-17_graph_memory_architecture_note.md §8.2; verse_docs/technical_architecture/2026-04-17_verse_graph_contribution_protocol_v0_1.md	Planned downstream layer

Target	Projection	Canonical doc	Status
Navigator pipeline scorer / annotation / parent-picker slots	Graph Cartography projection (aggregates: co-visit, co-activation, cluster stability, frame-reformation, bridge emphasis)	subsystem_history/2026-04-21_graph_runtime_projection_layer_plan.md; navigator/navigator_projection_spec.md	Plan; fills declared pipeline slots
Canvas ambient effects	Cartographic overlays (hotspot halos, heat, tidal influence, edge tension — consuming GC aggregates)	research/2026-03-27_ambient_graph_visual_effects.md; graph/2026-04-03_semantic_clustering_follow_on_plan.md	Research; downstream of GC

Target	Projection	Canonical doc	Status
History Manager (mixed timeline tab)	Mixed timeline projection (WAL → typed union with filter)	subsystem_history/2026-03-18_mixed_timeline_contract.md	Live
Navigator Recent section	Traversal projection (WAL → recent-history rows with activity annotation)	subsystem_history/SUBSYSTEM_HISTORY.md §4.1; NAVIGATOR.md §8	Live (read-only, per SUBSYSTEM_HISTORY §0A.7 shared-projection policy)
Node pane history surface	Node navigation history projection	subsystem_history/SUBSYSTEM_HISTORY.md §9	Live
Node pane audit surface	Node audit history projection	subsystem_history/node_audit_log_spec.md	Live

Target	Projection	Canonical doc	Status
Thread-shaped Navigator view	Constellation projection (anchor + replies/references/frontier → cluster layout)	navigator/2026-04-09_constellation_projection_plan.md	Plan
Semantic cluster assignment	Semantic clustering projection (embeddings → cluster membership, centroid, label)	graph/2026-04-03_semantic_clustering_follow_on_plan.md	Plan
Discovery / constellation frontier	Discovery pack manifest projection	navigator/2026-04-09_discovery_pack_manifest_and_install_flow.md	Plan
Source subscription health	Source health projection	navigator/2026-04-09_source_subscription_manager_and_health.md	Plan
Facet navigation surface	PMEST faceted filter projection	graph/faceted_filter_surface_spec.md; graph/facet_pane_routing_spec.md	Live/partial
Accessibility tree	UxTree projection (UI structure → AccessKit-compatible node tree)	subsystem_ux_semantics/ux_tree_and_probe_spec.md; subsystem_ux_semantics/ux_event_dispatch_spec.md	Live
Diagnostics pane	Diagnostic channel projection (runtime signals → channel schema + analyzers)	subsystem_diagnostics/SUBSYSTEM_DIAGNOSTICS.md	Live

Mechanisms that implement projections (not projections themselves):

Mechanism	Role	Canonical doc
Navigator projection pipeline (five-stage: Scope → Shape → Annotation → Presentation → Portal)	Navigator projection mechanism	navigator/navigator_projection_spec.md; ../../archive_docs/checkpoint_2026-04-23/graphshell_docs/implementation_strategy/navigator/2026-04-21_navigator_projection_pipeline_plan.md
ProjectionLens (Rust enum in graph-tree)	Shape-stage mechanism for tree-family projections; variants parameterize which edge family drives parent-child	technical_architecture/graph_tree_spec.md §6.7
LayoutMode (Rust enum in graph-tree)	Presentation-stage mechanism for tree-family projections (TreeStyleTabs, FlatTabs, SplitPanes, Hybrid)	technical_architecture/graph_tree_spec.md §6
NavAction / TreeIntent	Portal-stage mechanism for tree-family projections	technical_architecture/graph_tree_spec.md §6.8
GraphTreeRenderer adapters (egui / iced / web)	Presentation-stage framework adapters	technical_architecture/graph_tree_spec.md §4
CompositorAdapter	Composition pass mechanism for node viewer pane rendering	aspect_render/frame_assembly_and_compositor_spec.md
LensCompositor	Composes Layout + Presentation + Knowledge + Filters (the Lens concept — distinct from ProjectionLens)	system/register/lens_compositor_spec.md

• Viewer resolution and canvas rendering aren't currently framed as projections. They structurally are — both take graph truth and produce a representation for consumption in another layer. Naming them this way would align language without changing behavior.
• Non-tree Shape-stage mechanisms are missing. ProjectionLens covers tree/tab/split presentations via LayoutMode. Graphlet-as-graph (radial, corridor, atlas), time-axis, and summary/minimap shapes need their own Shape-stage mechanisms wrapped by the same pipeline.
• The Lens concept and ProjectionLens are distinct. Lens (per TERMINOLOGY.md Visual System) = Layout + Theme + Physics Profile + Filter — a configurable graph appearance/motion composition. ProjectionLens = a Shape-stage enum for tree-family projections. They do not collide architecturally but share a word; the three-form convention helps ("a projection produced under the Recency ProjectionLens" vs. "the active Lens is Liquid").
• Contribution projection is named but not yet built. Graph-memory note §8.2 describes it; VGCP §8, §9.2, §9.5 defines its target shape. A producing plan is outstanding.
• Cartography aggregates render as annotations, not as edges. See GC plan Phase 5 — the EdgeKind taxonomy stays closed; aggregates surface through the annotation registry (projection pipeline A3).

• Any new domain-pair projection adds a row here in the same session as its canonical plan/spec (DOC_POLICY §6.1 DOC_README update also applies).
• When a projection pattern is retired, mark the row archived rather than deleting it (fallback historical reference).
• When a structurally-present-but-unnamed projection (e.g., Viewer resolution) gets a canonical name, move its row from the "not previously named" flag to the regular listing.