# Cross-section line edits

The Sections-view toolbar in the project frame includes six commands for editing the polyline data of a single line definition within a cross-section. Each command works either on the **active section only** or across a **chainage range** (batch mode). Both modes share the same dialog; selecting the chainage-range radio button enables the From/To fields.

| Toolbar button | Effect |
|---|---|
| **Copy Line**         | Copies the source line's points + bulges + closed-state into the target line. |
| **Move Line**         | Same as Copy, then clears the source line's data — a cut-and-paste between line slots. |
| **Offset Line**       | Computes a parallel offset of the source line and writes it into the target. Distance is signed: **+ moves outside (away from the alignment axis); − moves inside (toward the axis)**. |
| **Delete Line**       | Clears all points of one line. |
| **Remove Duplicates** | Drops consecutive points whose 2D distance from the previous kept point is below a tolerance (metres). Preserves bulges of kept points and the line's closed-state. |
| **Translate Line**    | Shifts every point of one line by `(dX, dY)` in metres. Z, bulges, and closed-state unchanged. |

## Common dialog elements

- **Source line / Target line** — dropdowns of all measured line definitions in the active alignment. For Move and Copy, source and target must be different. For Offset, source = target is permitted (in-place offset). For Delete, Remove Duplicates and Translate Line there is only one **Line** dropdown.
- **Apply to**
  - **Active section only** — runs on the currently selected section in the Sections view.
  - **Chainage range** — iterates every cross-section whose station falls in the inclusive range. The From/To fields default to the alignment's first and last stations.
- **Skip sections where target already has data** (Copy / Move / Offset) — when checked, sections whose target slot already has points are left untouched and counted in the post-run summary as "skipped".

After OK, a summary box reports `Visited N section(s). Applied: M. Skipped: K (target had data) / L (source empty).` Counts equal `Visited` (every visited section is either applied or skipped).

When the run touches the active cross-section, the section canvas reloads from the updated model immediately — no manual refresh, no need to switch sections and back.

## Offset side rule

For each segment of the source polyline, "outside" is the perpendicular direction whose midpoint moves *farther* from the alignment axis (the `(0, 0)` point in the section's offset/elevation plane). For a tunnel polyline that wraps around the section interior, this consistently means away from the tunnel axis. For unusual line shapes (e.g., a short measured line off to one side) the rule may pick a counterintuitive side; in that case use a negative distance to flip.

## Behavior matrix

| Pre-condition | Copy | Move | Offset | Delete |
|---|---|---|---|---|
| Source has no points | Skipped: source empty | Skipped: source empty | Skipped: source empty | Skipped: line already empty |
| Target already has data, "Skip" checkbox on | Skipped: target had data | Skipped: target had data | Skipped: target had data | n/a |
| Source = target | Rejected (OK disabled) | Rejected | In-place offset (allowed) | n/a |

## Remove Duplicates dialog

- **Tolerance (m)** — the maximum 2D distance between consecutive points that still counts as a duplicate. Defaults to `0.005` (5 mm). The first point is always kept; subsequent points whose distance from the most recent kept point is **at or below** the tolerance are dropped. The bulge that travels with each kept point is preserved.
- The summary reports `Visited N section(s). Modified: M. Skipped: K (line empty).` Sections where the scan finds no duplicates are counted as visited but not modified.

## Translate Line dialog

- **dX (m) / dY (m)** — translation vector in the section's local offset/elevation plane. X follows the line-definition's offset axis (right-positive), Y follows elevation. Both can be negative. Translating by `(0, 0)` is rejected at the dialog (OK button stays disabled).
- Every point of the chosen line is shifted by `(dX, dY)`; Z is preserved. Bulges and closed-state are unchanged.
- The summary reports `Visited N section(s). Modified: M. Skipped: K (line empty).`

## Notes

- **Bulges:** Copy, Move, Remove Duplicates, and Translate Line preserve bulges exactly. Offset drops bulges (output polyline is straight-segment only). Acceptable accuracy for tunnel measured lines; revisit if exact-arc lines start using these commands.
- **Closed state:** Copy and Move mirror the source's `coDefault` / `coForceClosed` / `coForceOpen` override. Offset, Remove Duplicates, and Translate Line preserve the source's closed state.
- **Self-intersection:** A closed polyline offset inward beyond its inradius will self-intersect. v1 emits the raw self-intersecting polyline; clean it up by hand or undo.
- **Undo:** Batch operations are not undoable as a single transaction. Confirm the summary box's counts before continuing.

## Section metadata

Each tunnel can declare a set of metadata fields (excavation date,
blast number, crew name, free-form notes…). Field schema is defined
per tunnel; values are entered per cross-section.

### Defining the schema

1. Open *Tunnel Settings…* on the active alignment.
2. Switch to the **Metadata Fields** tab.
3. Click **Add Field**, enter a name (`[A-Za-z0-9_]`), pick a Type.
   Optionally tick *Required* and fill *Default* / *Description*.
4. For *Enum* type, click **Edit Enum Values…** to add the allowed
   choices.
5. Buttons **Move Up** / **Move Down** reorder the schema; **Remove
   Field** drops a definition (with a confirm prompt that names how
   many sections have values to clear).

New tunnels start with three example fields: `ExcavationDate` (date),
`BlastNumber` (integer), `Notes` (text). Delete what you don't need.

### Entering values per section

Right-click a cross-section in the project tree → **Edit Metadata…**
to open the per-section editor. Each field renders its own widget:

| Field type | Widget |
|---|---|
| Text | text edit |
| Integer | number-only edit with up/down arrows |
| Number | floating-point edit |
| Date | date picker (`yyyy-mm-dd`) |
| Boolean | checkbox |
| Enum | dropdown of the allowed values |

*OK* commits; *Cancel* discards every change made in the dialog.

### Using metadata in layouts

Layout TEXT entities can inject metadata via the `META` field:

| ProviderArgs | Result |
|---|---|
| `field=META, meta=ExcavationDate` | `2026-04-15` (default `yyyy-mm-dd`) |
| `field=META, meta=ExcavationDate, fmt=dd/mm/yyyy` | `15/04/2026` |
| `field=META, meta=BlastNumber, prefix=Blast #` | `Blast #42` |
| `field=META, meta=Crew` | `Alpha` (the canonical case from the schema) |

### Activity log

Schema mutations (add/rename/type-change/remove) and per-section
value commits land in the project's activity log under the
`metadata` category, viewable in the Calendar workspace.

### Round-tripping with LandXML

Both the schema and the per-section values round-trip through LandXML
import/export. The export dialog has an opt-out **"Include section
metadata"** checkbox under TunnelCAD Extension Details (default on).
Old LandXML files without metadata extensions load with the
alignment's seeded defaults.

### Bulk editing (matrix view)

For long station lists, the per-section editor is slow. Right-click a
tunnel in the project tree → **Edit Metadata Matrix...** to open a
spreadsheet-style grid: rows are sections in chainage order; columns
are Station / Name / one per metadata field. Per-column editors switch
automatically (text / number / date / checkbox / dropdown). Three
helpers above the grid:

- **Fill Down** copies the active cell's value into every selected row
  below it (single column at a time).
- **Clear** wipes selected metadata cells back to empty.
- **Paste** drops a tab-separated rectangular block from the
  clipboard — works for paste-from-Excel.

OK commits; Cancel restores the snapshot taken when the dialog opened.

The Metadata Fields tab in *Tunnel Settings* also has an **Edit
Matrix...** button so you can jump straight from defining a new field
to filling values across every section.

### Including metadata in DXF exports

The Sections-to-DXF export dialog has a per-mode checkbox:

- **Mode A** (per-section local plane) → captions appear on a
  `METADATA` layer below each section's bounding box.
- **Mode C** (atlas / sheet layout) → captions appear inside each
  cell, stacked below the title line.
- **Mode B** (combined world XYZ) does **not** offer the option —
  3D-stacked text labels are illegible.

Each non-empty metadata value emits one `Field: Value` line. Empty
values are skipped. Off by default.

### Including metadata in PDF reports

The three section-level PDF reports (Line Data / Line vs Theoretical /
DR Trend) have a per-dialog checkbox **Include section metadata**
(default off). When on:

- The PDF gains a small two-column metadata table at the top of each
  per-section detail page (one row per non-empty value).
- The XLSX export adds one column per metadata field at the right end
  of the per-section sheet — handy for pivot tables.

### Mass Table

The Mass Table dialog has its own **Show metadata columns** checkbox.
When on, the grid + every export (CSV / XLSX / PDF) gain one column
per defined metadata field, formatted per the field's type.

## Edit Line Data

For typing-based corrections to measured-line points (paste from
Excel, fix a bad offset by typing, reorder rows), open the **Edit
Line Data...** dialog from the section toolbar or the project-tree
right-click on a cross-section.

The dialog shows one cross-section's chosen line as a grid:

| Column          | Meaning                                                                                  | Editable |
|-----------------|------------------------------------------------------------------------------------------|----------|
| `#`             | Point index (auto-numbered).                                                             | no       |
| `Offset (m)`    | Lateral offset from the alignment axis.                                                  | yes      |
| `Elevation (m)` | Vertical position on the section's local plane.                                          | yes      |
| `DR (mm)`       | Computed deviation from the line's reference (template or measured). `--` when no reference is configured. Recomputes live as you type Offset/Elevation. | no |

The `#` and `DR` columns are read-only — the in-cell editor will
not open for them.

Switch lines via the **Line** combo at the top — pending edits to
the previous line are kept until you click OK or Cancel. Buttons on
the right add/delete rows, move the active row up/down, reverse the
whole point order, sort all rows by ascending Offset (**Sort by X**),
or toggle the line's Closed flag.

OK commits all changes; Cancel restores every line modified during
the dialog session, including pre-existing bulges that the dialog
doesn't surface as columns.

Pasted values follow the standard `TStringGrid` paste path — copy a
2-column block from Excel and paste into the Offset/Elevation pair
to bulk-update points.