# 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