sec_interp.gui.adapters.structure_extractor module

Structure extraction adapter (Extract phase).

Bridges the QGIS object world and the QGIS-agnostic core layer for structural measurements. It reads the section line and structure layers, buffers the line, filters features within the buffer, and samples raster elevations — returning plain tuples/dicts so StructureService never touches QGIS objects.

class sec_interp.gui.adapters.structure_extractor.SectionContext(line_points: list[tuple[float, float]]=<factory>, line_start: tuple[float, float]=(0.0, 0.0), line_azimuth: float = 0.0, structures: list[dict[str, ~typing.Any]]=<factory>)

Bases: object

Extracted section data (QGIS-agnostic primitives).

line_points

Section line vertices as (x, y) tuples.

Type:

list[tuple[float, float]]

line_start

First vertex of the section line.

Type:

tuple[float, float]

line_azimuth

Compass bearing of the section line.

Type:

float

structures

Detached structures as {"point": (x, y), "attributes": {...}}.

Type:

list[dict[str, Any]]

line_azimuth: float = 0.0

line_points: list[tuple[float, float]]

line_start: tuple[float, float] = (0.0, 0.0)

structures: list[dict[str, Any]]

class sec_interp.gui.adapters.structure_extractor.StructureExtractor

Bases: object

Extract structure-related data from QGIS layers into primitives.

detach_structures(struct_lyr: qgis.core.QgsVectorLayer, line_geom: qgis.core.QgsGeometry, buffer_m: float) → list[dict[str, Any]]

Buffer the line and extract structures within it.

Returns a list of {"point": (x, y), "attributes": {...}} dicts.

extract_line(line_geom: qgis.core.QgsGeometry) → tuple[list[tuple[float, float]], tuple[float, float], float]

Extract (line_points, line_start, line_azimuth) from a geometry.

Parameters:

line_geom – The section line geometry.

Returns:

A tuple of line vertices, the start vertex, and the compass bearing.

extract_section_and_structures(line_lyr: qgis.core.QgsVectorLayer, struct_lyr: qgis.core.QgsVectorLayer, buffer_m: float, feature_id: int | None = None) → SectionContext | None

Extract the section line geometry and structures within the buffer.

Parameters:

• line_lyr – The cross-section line vector layer.

• struct_lyr – The structural measurements vector layer.

• buffer_m – Buffer distance (in line-layer units).

• feature_id – Section feature id (first feature when None).

Returns:

A SectionContext of primitives, or None if the line layer has no valid geometry.

make_elevation_sampler(raster_lyr: QgsRasterLayer, line_lyr: QgsVectorLayer | None = None, band_number: int = 1) → Callable[[float, float], float]

Return an (x, y) -> elevation sampler reprojecting to the raster CRS.

Structural points live in the section line CRS. When the DEM uses a different CRS (on-the-fly reprojection) they must be transformed before sampling, otherwise every elevation comes back as 0. The transform is resolved once here and reused for every point.

sample_elevation(raster_lyr: QgsRasterLayer, x: float, y: float, band_number: int = 1, line_lyr: QgsVectorLayer | None = None) → float

Sample a single elevation value from a raster layer.

Parameters:

• raster_lyr – The DEM raster layer.

• x – X coordinate to sample (in the section line CRS).

• y – Y coordinate to sample (in the section line CRS).

• band_number – Raster band index (default 1).

• line_lyr – Section line layer, used to reproject the point.

Returns:

The sampled elevation, or 0.0 if the raster is invalid or the point is out of bounds.