Analysis Modes¶

The Analytics module supports two comparison modes, selectable from the Mode dropdown in the ribbon toolbar or the dashboard frame.

Measured vs Template¶

The standard analysis mode. A measured survey line is compared against the theoretical design line (template) at each cross-section.

The template is automatically interpolated at each section’s chainage using GetTemplateAtStation. If the template changes along the alignment (e.g., wider at portals, narrower in the bore), the correct template geometry is used for each section.

Use cases for Measured vs Template¶

Excavation quality assessment: Compare “Excavation” line against “Design Excavation” template to evaluate how accurately the tunnel was excavated
Shotcrete compliance: Compare “Shotcrete” line against “Design Shotcrete” template to verify that the shotcrete layer conforms to the design
Lining thickness: Compare “Inner Lining” line against “Lining Design” template

Reference combo in Template mode¶

When this mode is selected, the Reference combo lists all template line definitions from the active alignment (TemplateLineDefinitions).

Measured vs Measured¶

Compares two measured lines from the same cross-section. Instead of using a template as the reference, a second measured line definition serves as the baseline.

Both lines must exist in the same cross-section. The deviation engine computes deviations identically – the first line (Measured) is compared against the second line (Reference), with positive deviations indicating the measured line is outside the reference and negative deviations indicating it is inside.

Use cases for Measured vs Measured¶

Before/after shotcrete: Compare “Excavation” (before) vs “Shotcrete” (after) to evaluate shotcrete layer thickness and uniformity
Deformation monitoring: Compare “Epoch 1” vs “Epoch 2” measurements at the same stations to detect ground convergence or tunnel deformation over time
Method comparison: Compare “Laser Scan” vs “Total Station” to validate measurement consistency between survey methods
Construction stages: Compare “First Pass” vs “Second Pass” in a multi-stage excavation

Reference combo in Measured mode¶

When this mode is selected, the Reference combo lists all measured line definitions from the active alignment (LineDefinitions) – the same list as the Measured combo. You can select any two different lines.

Warning

When comparing two measured lines, ensure both lines have data at the same cross-sections. Sections where either line is missing will be skipped. The chainage range filter helps focus on sections where both lines are available.

Engine behavior¶

The deviation engine (TTunnelDeviationEngine) is polyline-agnostic – it does not distinguish between “measured” and “template” geometries. It simply compares two point arrays:

First array (measured): The profile being evaluated
Second array (reference): The baseline for comparison

All computations – RMS, overbreak/underbreak areas, compliance sectors, tolerance metrics – work identically in both modes. The only difference is the source of the reference polyline:

Mode	Reference source	Display name
Measured vs Template	`TTemplateLine.Entity.GetWorldPoly`	Template section name
Measured vs Measured	`TSectionLineData.Points`	Measured line definition name

Switching modes¶

Changing the mode immediately repopulates the Reference combo with the appropriate line definitions (template or measured). The previously selected reference is cleared, and the first available line is auto-selected.

Tip

When using Measured vs Measured mode for deformation analysis, set up a tolerance band (e.g., +/-5mm) to quantify the agreement between epochs. The Cpk index will indicate whether deformations are within acceptable limits.