SecInterp - Technical Compendium

This document consolidates technical research, geophysical algorithms, and API references for the SecInterp plugin.

🔬 Scientific & Geophysical Research

1. Integration of Geophysics

The plugin is prepared for future integration of deep geophysical data:

  • Potential (SP): Projections use normalized dot product for section alignment and absolute elevation calculation ($Z_{collar} - Depth$).

  • VES (SEV): Resistivity models are visualized as blocks on a logarithmic scale ($\log_{10}(Rho)$) using thickness-to-elevation conversion.

2. Drillhole Modeling

  • Desurveying: Trayectories are calculated using the Average Angle Method (Tangential tracking).

  • Projection: 3D trajectories are mapped to the 2D plane by calculating distance along the section line while preserving absolute Z.

3. Core Algorithms

  • Distance & Sampling: We use QgsDistanceArea.measureLine() and direct dataProvider() access for DEM sampling, yielding a ~30% performance boost over high-level processing algorithms.

  • Adaptive LOD: Uses the Douglas-Peucker (RDP) algorithm for line simplification and a curvature-based hysteresis logic to adjust sampling density dynamically during zoom.

🔧 API Reference

Core Services (core/services/)

ProfileService

  • generate_topographic_profile(line_lyr, raster_lyr, band): Samples raster data along a line.

  • Returns: List[Tuple[float, float]] (distance, elevation).

GeologyService

  • generate_geological_profile(...): Intersects section lines with geological geometry.

  • Returns: List[GeologySegment].

StructureService

  • project_structures(...): Projects 3D structural data and calculates apparent dip.

  • Formula: tan(beta) = tan(alpha) * |cos(strike - azimuth)|.

DrillholeService

  • Architecture: Decomposed into specialized processors (CollarProcessor, SurveyProcessor, IntervalProcessor).

  • project_collars(): Projects collar points 3D->2D.

  • process_intervals(): Handles full pipeline for trace and interval generation.

🛡️ Validation Framework

Modularized in core/validation/:

  • FieldValidator: Numeric and existence checks.

  • LayerValidator: CS, geometry, and feature count validation.

  • PathValidator: Security and permission handling.

  • ProjectValidator: High-level orchestration.

🧬 Key Data Structures

GeologySegment

Used to represent both surface outcrops and drillhole intervals.

@dataclass
class GeologySegment:
    unit_name: str
    points: List[Tuple[float, float]]
    geometry: QgsGeometry
    attributes: Dict[str, Any]

StructureMeasurement

@dataclass
class StructureMeasurement:
    distance: float
    elevation: float
    apparent_dip: float
    original_dip: float
    original_strike: float