Harris Matrix (stratigraphic relations)

BraDypUS supports stratigraphic unit (US) relationship management with a built-in Harris Matrix visualisation. The feature is available for any table that has the RS plugin enabled.

Enabling the RS system

In Config → Tables → System plugins, toggle the Stratigraphic relations switch on. This enables the RS panel in RecordView and the Harris Matrix button in DataView.

The table's ID field (configured under Layout) is used as the human-readable label shown in the RS panel and the matrix. The relations are stored in the database using the integer record id as a foreign key, ensuring referential integrity.

Stratigraphic relation types

There are ten relation types organised in five inverse pairs. Relations 9 and 10 are symmetric (self-inverse).

Code	Label	Inverse
1	Is covered by	5 — Covers
2	Is cut by	6 — Cuts
3	Carries	7 — Leans against
4	Is filled by	8 — Fills
5	Covers	1 — Is covered by
6	Cuts	2 — Is cut by
7	Leans against	3 — Carries
8	Fills	4 — Is filled by
9	Is the same as	9 (symmetric)
10	Is bound to	10 (symmetric)

Directed relations (1–8) are stored as a single row with direction; you only need to enter one direction and the inverse is handled automatically. Relations 9 and 10 have no directionality.

Managing relations in RecordView

The RS panel in RecordView shows all relations for the current record.

To add a relation:

1. Select the relation type from the dropdown.
2. Start typing in the search box to find the other unit — an autocomplete list shows matching records from the same table. Select the desired unit.
3. Click Add.

To remove a relation: click the delete icon next to it.

Harris Matrix view

Click Harris Matrix in the DataView toolbar to open a full-page interactive matrix for all records in the current table (respecting the active search filter).

• Nodes represent individual stratigraphic units.
• Directed arrows represent the covers relationship (newer → older).
• Undirected dashed lines represent equivalences and contemporaneity.
• Units outside the active filter are shown with a dashed border.
• Click a node to navigate to that record.

Subset matrix

Apply a search filter in DataView before opening the Harris Matrix to see only the selected units. Units that are related to the filtered set but not themselves in the filter are shown in a lighter style (in-context but not in-filter).

Export

Click Export PNG in the Matrix toolbar to save the current view as a high-resolution PNG image.

Absolute chronological timeline

When the fuzzy-date plugin is active on the same table, a Chronological toggle appears in the Matrix toolbar.

Layout	Description
Stratigraphic	Standard Harris Matrix — nodes positioned by topological depth (default).
Chronological	Nodes positioned on a vertical year axis according to their chrono_from / chrono_to values. The horizontal columns from the stratigraphic layout are preserved, so stratigraphic position and calendar time are both visible simultaneously.

In chronological mode:

• Older units appear lower on the axis; newer units appear higher.
• The vertical distance between nodes reflects the time gap between events.
• Nodes whose date type is ante quem or post quem are positioned at the known bound.
• Undated nodes are placed below the dated zone, marked with an italic label.
• The SVG axis on the left shows year labels calibrated to the data range.
• Edges still connect units by their stratigraphic relationship.
• Edit mode is not available in chronological layout (read-only view).

Why is this useful?

Traditional Harris Matrix tools show which unit comes before another, but not by how much. The chronological layout reveals the real time gaps — a stratigraphically short sequence may span centuries, while a long sequence may compress into decades.