fix(map): make area analysis scale-aware

backend/app/services/vector_feature_service.py

@@ -11,7 +11,7 @@ from geoalchemy2.shape import to_shape
 from shapely.geometry import box, mapping, shape
 from shapely.ops import transform as transform_geometry
 from shapely.validation import make_valid
-from sqlalchemy import Float, cast, func
+from sqlalchemy import Float, String, cast, func
 
 from app.core.errors import AppError
 from app.models import Dataset, VectorFeature
@@ -548,6 +548,8 @@ class VectorFeatureService:
         selection_area_id: UUID | None = None,
         full_dataset_area: bool = False,
         preclipped_partition_filter: tuple[str, str] | None = None,
+        dataset_ids: list[UUID] | None = None,
+        deduplicate_source_features: bool = False,
     ) -> dict[str, Any]:
         normalized_bbox = VectorFeatureService._normalize_selection_bbox(bbox)
         safe_limit = max(1, min(int(limit), 1000))
@@ -561,13 +563,19 @@ class VectorFeatureService:
                 4326,
             )
 
-        query = db.query(VectorFeature).filter(VectorFeature.dataset_id == dataset_id)
+        selected_dataset_ids = dataset_ids or [dataset_id]
+        query = db.query(VectorFeature).filter(VectorFeature.dataset_id.in_(selected_dataset_ids))
         if preclipped_partition_filter is not None:
             partition_property, partition_value = preclipped_partition_filter
             query = query.filter(VectorFeature.properties_json.op("->>")(partition_property) == partition_value)
         if not full_dataset_area:
             query = query.filter(ST_Intersects(VectorFeature.geometry, selection_shape))
-        if hasattr(query, "count"):
+        if deduplicate_source_features:
+            identity = func.coalesce(VectorFeature.source_feature_id, cast(VectorFeature.id, String))
+            total_feature_count = int(
+                query.with_entities(func.count(func.distinct(identity))).scalar() or 0
+            )
+        elif hasattr(query, "count"):
             total_feature_count = int(query.count())
         else:  # Lightweight unit-test sessions do not always implement Query.count().
             total_feature_count = len(query.all())
@@ -585,6 +593,7 @@ class VectorFeatureService:
             summary = VectorFeatureService.summarize_features_by_bbox(
                 db,
                 dataset=dataset,
+                dataset_ids=selected_dataset_ids,
                 bbox=normalized_bbox,
                 total_feature_count=total_feature_count,
                 selection_geometry=selection_geometry,