feat: add semantic GIS selection metrics

scripts/provision_regional_grb_context.py

@@ -69,7 +69,11 @@ class LayerDefinition:
     reference_layer_name: str
     layer_type: str
     geometry_types: tuple[str, ...]
+    metric_key: str
+    metric_method: str
     metric_label: str
+    metric_unit: str
+    metric_warning: str | None
     limitation_message: str
 
 
@@ -80,7 +84,11 @@ LAYERS = (
         reference_layer_name="roads",
         layer_type="road",
         geometry_types=("LineString", "MultiLineString"),
-        metric_label="Wegen",
+        metric_key="road_length",
+        metric_method="intersection_length",
+        metric_label="Totale weglengte",
+        metric_unit="km",
+        metric_warning="De lengte volgt de GRB-wegsegmenten en zegt niets over rijstroken, verkeersvolume of verhardingsoppervlakte.",
         limitation_message="GRB Wegsegment represents road-network line segments, not traffic volume or routing suitability.",
     ),
     LayerDefinition(
@@ -93,7 +101,11 @@ LAYERS = (
         reference_layer_name="water",
         layer_type="water",
         geometry_types=("LineString", "MultiLineString", "Polygon", "MultiPolygon"),
-        metric_label="Waterobjecten",
+        metric_key="water_area",
+        metric_method="intersection_area",
+        metric_label="Wateroppervlakte",
+        metric_unit="ha",
+        metric_warning="Watervolume is niet berekenbaar zonder betrouwbare diepte- of bathymetrische gegevens. De kaartbron levert alleen oppervlakte- en lijngeometrie.",
         limitation_message="GRB water combines surface-water polygons and water-related line collections; counts are object counts, not water volume.",
     ),
     LayerDefinition(
@@ -102,7 +114,11 @@ LAYERS = (
         reference_layer_name="parcels",
         layer_type="parcel",
         geometry_types=("Polygon", "MultiPolygon"),
-        metric_label="Percelen",
+        metric_key="parcel_area",
+        metric_method="intersection_area",
+        metric_label="Perceeloppervlakte",
+        metric_unit="ha",
+        metric_warning="GRB-percelen zijn een grafische referentie en vormen geen juridische grensopmeting.",
         limitation_message="GRB ADP is a graphical representation of the presumed cadastral parcel location and is not a legal boundary survey.",
     ),
 )
@@ -721,10 +737,12 @@ def provision_dataset(
         "partition_count": len(partition_paths),
         "partition_strategy": manifest["partition_strategy"],
         "selection_aggregation": {
-            "method": "feature_count",
+            "metric_key": definition.metric_key,
+            "method": definition.metric_method,
             "label": definition.metric_label,
-            "unit": "objecten",
+            "unit": definition.metric_unit,
             "is_estimate": False,
+            "warning": definition.metric_warning,
         },
         "attribution": GRB_ATTRIBUTION,
     }