sec_interp.gui.adapters.geometry module

Geometry extraction adapter (Extract phase).

Compatibility facade for the QGIS-dependent geometry helpers. The implementation is split by concern:

  • geometry_crs: distance area, CRS transforms and sampling intervals.

  • geometry_lines: vertex extraction, densification and segment ranges.

  • geometry_sampling: point and line raster sampling.

  • geometry_stats: per-cell profile statistics.

  • geometry_sections: section-feature resolution and profile context.

These perform the “Extract” step of the Extract-then-Compute pattern; the core layer stays QGIS-agnostic.

class sec_interp.gui.adapters.geometry.ProfileRasterStats(count: int, minimum: float, maximum: float, mean: float, resolution: float, length: float)

Bases: object

Read-only elevation statistics of the section over the DEM.

count

Number of distinct raster cells sampled.

Type:

int

minimum

Minimum elevation (m).

Type:

float

maximum

Maximum elevation (m).

Type:

float

mean

Mean elevation (m).

Type:

float

resolution

Sampling interval in line-CRS units (raster pixel size).

Type:

float

length

Total sampled distance along the line (line-CRS units).

Type:

float

count: int
length: float
maximum: float
mean: float
minimum: float
resolution: float
sec_interp.gui.adapters.geometry.build_sampling_transform(line_crs: QgsCoordinateReferenceSystem | None, raster_layer: QgsRasterLayer) → QgsCoordinateTransform | None

Build a transform from the line CRS to the raster CRS, or None.

A transform is only needed when both CRSs are known and differ. Across different CRSs, sampling with raw layer coordinates reads the wrong pixels.

Parameters:

  • line_crs – CRS of the section line (None if unknown).

  • raster_layer – The DEM/raster layer being sampled.

Returns:

A QgsCoordinateTransform (line -> raster) or None when the CRSs match, are unknown, or the transform cannot be created.

sec_interp.gui.adapters.geometry.calculate_segment_range(seg_geom: qgis.core.QgsGeometry, line_start: qgis.core.QgsPointXY, da: qgis.core.QgsDistanceArea) → tuple[float, float] | None

Calculate the start and end distance for a segment geometry along the line.

sec_interp.gui.adapters.geometry.create_distance_area(crs: qgis.core.QgsCoordinateReferenceSystem) → qgis.core.QgsDistanceArea

Create and configure a QgsDistanceArea object.

sec_interp.gui.adapters.geometry.densify_line_by_interval(geometry: qgis.core.QgsGeometry, interval: float) → qgis.core.QgsGeometry

Densify a line geometry by a specific distance interval.

sec_interp.gui.adapters.geometry.extract_all_vertices(geometry: qgis.core.QgsGeometry) → list[qgis.core.QgsPointXY]

Extract all vertices from any QGIS geometry type.

sec_interp.gui.adapters.geometry.extract_lines_from_geometry(geometry: qgis.core.QgsGeometry) → list[qgis.core.QgsGeometry]

Extract individual LineString geometries from a (possibly Multi) geometry.

sec_interp.gui.adapters.geometry.get_line_vertices(geometry: qgis.core.QgsGeometry) → list[qgis.core.QgsPointXY]

Extract vertices specifically from a line or multiline geometry.

sec_interp.gui.adapters.geometry.line_length(line_lyr: qgis.core.QgsVectorLayer, feature_id: int | None = None) → float | None

Return the length of the section feature’s geometry in a line layer.

sec_interp.gui.adapters.geometry.prepare_profile_context(line_lyr: qgis.core.QgsVectorLayer, feature_id: int | None = None) → tuple[qgis.core.QgsGeometry, qgis.core.QgsPointXY, qgis.core.QgsDistanceArea]

Prepare a common context for profile calculation operations.

sec_interp.gui.adapters.geometry.profile_raster_statistics(line_geom: qgis.core.QgsGeometry, raster_layer: qgis.core.QgsRasterLayer, band_number: int, distance_area: qgis.core.QgsDistanceArea) → ProfileRasterStats | None

Compute min/max/mean elevation over unique DEM cells along the line.

Densifies at the CRS-aware raster resolution, reprojects each sample into the raster CRS and collapses samples that fall in the same pixel cell (so repeated cells from the densification do not bias min/max/mean). Returns None when there is nothing usable to sample.

sec_interp.gui.adapters.geometry.raster_resolution_in_crs(raster_layer: QgsRasterLayer, target_crs: QgsCoordinateReferenceSystem | None) → float | None

Return the raster pixel size expressed in target_crs units.

rasterUnitsPerPixelX() is expressed in the raster’s own CRS. When the section line lives in a different CRS (on-the-fly reprojection), using that value directly as a sampling interval is meaningless and can densify the line into millions of vertices. This transforms a one-pixel-long segment from the raster CRS into target_crs to recover a usable interval.

Parameters:

  • raster_layer – The DEM/raster layer.

  • target_crs – CRS in which to express the resolution (None to return the raw value).

Returns:

Pixel size in target_crs units, or None if it cannot be determined.

sec_interp.gui.adapters.geometry.resolve_sampling_interval(geometry: QgsGeometry, raster_layer: QgsRasterLayer, line_crs: QgsCoordinateReferenceSystem | None) → float

Resolve a safe sampling interval for a raster profile.

Prefers the DEM pixel size expressed in the line’s CRS. Falls back to a length-derived interval when the resolution cannot be resolved, and always returns a strictly positive value.

Parameters:

  • geometry – The section line geometry (in line_crs units).

  • raster_layer – The DEM/raster layer.

  • line_crs – CRS of the section line (None if unknown).

Returns:

A positive sampling interval in line_crs units.

sec_interp.gui.adapters.geometry.resolve_section_feature(line_lyr: QgsVectorLayer | None, feature_id: int | None = None) → QgsFeature | None

Return the section feature to use (first by default, or feature_id).

This is the single resolution point for the section line, so every extractor picks the same feature. None returns the first feature; a fid filters by it. Defensive: an invalid layer or a missing feature returns None.

sec_interp.gui.adapters.geometry.resolve_section_geometry(line_lyr: QgsVectorLayer | None, feature_id: int | None = None) → QgsGeometry | None

Return the section feature geometry, or None when unavailable.

sec_interp.gui.adapters.geometry.sample_elevation_along_line(geometry: QgsGeometry, raster_layer: QgsRasterLayer, band_number: int, distance_area: QgsDistanceArea, reference_point: QgsPointXY | None = None, interval: float | None = None) → list[QgsPointXY]

Sample elevation values along a line geometry from a raster layer.

The sampling interval is the raster pixel size expressed in the section line’s CRS. When the line and raster CRSs differ (on-the-fly reprojection), the pixel size is transformed before use and each sample point is reprojected into the raster CRS.

sec_interp.gui.adapters.geometry.sample_point_elevation(raster_layer: QgsRasterLayer, point: Any, band_number: int = 1, source_crs: QgsCoordinateReferenceSystem | None = None) → float

Sample elevation from a raster layer at a 2D coordinate.

point may be a QgsPointXY or a (x, y) tuple. When source_crs differs from the raster CRS, the point is reprojected before sampling.

sec_interp.gui.adapters.geometry.section_line_start_point(geometry: qgis.core.QgsGeometry) → qgis.core.QgsPointXY

Return the first vertex of a line geometry (start of the section).