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geointel/backend/tests/test_vector_selection_partial_features.py
T
JensandClaude Opus 5 dd87a62e8f report what an area selection actually measured
Four ways a selection produced a confident number about a different area than
the operator drew:

Flood hazard divided the inundated cells by every cell in the drawn rectangle,
including cells the VMM raster does not model at all. A selection reaching
past the modelled extent therefore reported a diluted risk share, turning
missing data into an implied absence of risk. Terrain, bathymetry and thematic
raster already divided by valid cells; flood hazard was the outlier. It now
reports the three populations separately, states model coverage next to the
drawn area, and returns a null fraction rather than a zero when nothing was
modelled.

geometry_mask selects a cell when its centre falls inside the geometry, so a
rectangle smaller than one cell — or one landing between four centres —
selected nothing and the analysis returned zeros indistinguishable on screen
from "we looked and there is nothing here". On a 100 m population raster a
40 m rectangle over a city block reported no inhabitants. Selection now falls
back to the touched cells and says that it did, since the answer then covers
more ground than was requested. rasterio.mask applies the same centre rule
when cropping, so that call is widened too; the cells that count are still
decided by the centre rule wherever it selects anything.

The object count treated any feature touching the selection as whole, while
intersection_area clipped it — two headline numbers on one panel describing
different populations. The count stays whole-feature, which is what "objecten"
means to an operator, but now reports how many the edge cuts and is marked an
estimate when it does. The area_weighted_sum branch reuses that same count
instead of issuing its own near-identical query.

Partitioned selection de-duplicated the count on source_feature_id but
returned the raw rows, so a building on a municipal boundary was counted once
and drawn twice.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-22 14:33:19 +02:00

162 lines
5.1 KiB
Python

"""The object count and the area metric must describe the same selection.
``intersection_area`` clips a feature to the drawn rectangle, but the object
count treated any feature that merely touches the rectangle as wholly inside.
For a rectangle across a built-up area that overstates the count at every
edge, and the two headline numbers on the same panel then describe different
populations: "1.000 gebouwen" next to the clipped area of rather fewer.
The count now reports how many features lie entirely inside and how many are
cut by the selection edge, and is marked as an estimate when any are.
"""
from __future__ import annotations
from app.services.vector_feature_service import VectorFeatureService
def test_a_count_without_partial_features_is_exact() -> None:
disclosure = VectorFeatureService.count_disclosure(
total_feature_count=120,
fully_covered_feature_count=120,
)
assert disclosure["partially_covered_feature_count"] == 0
assert disclosure["is_estimate"] is False
assert disclosure["warning"] is None
def test_features_cut_by_the_selection_edge_are_reported() -> None:
disclosure = VectorFeatureService.count_disclosure(
total_feature_count=120,
fully_covered_feature_count=98,
)
assert disclosure["partially_covered_feature_count"] == 22
assert disclosure["is_estimate"] is True
assert "22" in disclosure["warning"]
assert "rand" in disclosure["warning"]
def test_a_selection_of_only_partial_features_is_still_coherent() -> None:
disclosure = VectorFeatureService.count_disclosure(
total_feature_count=3,
fully_covered_feature_count=0,
)
assert disclosure["partially_covered_feature_count"] == 3
assert disclosure["is_estimate"] is True
def test_an_empty_selection_makes_no_claim() -> None:
disclosure = VectorFeatureService.count_disclosure(
total_feature_count=0,
fully_covered_feature_count=0,
)
assert disclosure["partially_covered_feature_count"] == 0
assert disclosure["is_estimate"] is False
assert disclosure["warning"] is None
def test_a_preclipped_full_area_selection_has_no_edge_effect() -> None:
"""Selecting the whole work area cuts nothing; the count is exact."""
disclosure = VectorFeatureService.count_disclosure(
total_feature_count=500,
fully_covered_feature_count=None,
)
assert disclosure["partially_covered_feature_count"] is None
assert disclosure["is_estimate"] is False
assert disclosure["warning"] is None
def test_an_inconsistent_covered_count_never_produces_a_negative() -> None:
disclosure = VectorFeatureService.count_disclosure(
total_feature_count=10,
fully_covered_feature_count=14,
)
assert disclosure["partially_covered_feature_count"] == 0
assert disclosure["is_estimate"] is False
class _ScalarQuery:
def __init__(self, value):
self.value = value
def filter(self, *args): # noqa: ANN002, ARG002
return self
def scalar(self):
return self.value
class _SequenceSession:
"""Answers the summary's scalar queries in order: covered count, then metrics."""
def __init__(self, values):
self.values = iter(values)
def query(self, *args): # noqa: ANN002, ARG002
return _ScalarQuery(next(self.values))
def _buildings_dataset():
from uuid import uuid4
from app.models import Dataset
return Dataset(
id=uuid4(),
project_id=uuid4(),
name="grb-buildings.geojson",
dataset_type="vector",
dataset_role="reference",
source_name="grb",
reference_layer_name="buildings",
source_metadata={"theme": "buildings"},
)
BBOX = {"min_x": 5.0, "min_y": 51.1, "max_x": 5.2, "max_y": 51.3, "crs": "EPSG:4326"}
def test_summary_reports_the_edge_cut_next_to_the_object_count() -> None:
summary = VectorFeatureService.summarize_features_by_bbox(
_SequenceSession([88, 125_000.0]),
dataset=_buildings_dataset(),
bbox=BBOX,
total_feature_count=100,
)
assert summary["feature_count"] == 100
assert summary["fully_covered_feature_count"] == 88
assert summary["partially_covered_feature_count"] == 12
assert "12 van de 100" in summary["selection_edge_warning"]
count_metric = next(
item for item in summary["metrics"] if item["aggregation_method"] == "feature_count"
)
assert count_metric["is_estimate"] is True
assert "doorgesneden" in count_metric["warning"]
# The clipped area metric is exact and must not inherit the count's caveat.
area_metric = next(
item for item in summary["metrics"] if item["aggregation_method"] == "intersection_area"
)
assert area_metric["is_estimate"] is False
def test_summary_stays_exact_when_the_selection_cuts_nothing() -> None:
summary = VectorFeatureService.summarize_features_by_bbox(
_SequenceSession([100, 125_000.0]),
dataset=_buildings_dataset(),
bbox=BBOX,
total_feature_count=100,
)
assert summary["partially_covered_feature_count"] == 0
assert summary["selection_edge_warning"] is None