fix(platform): govern geospatial analysis and raster handoffs

backend/app/services/area_service.py

@@ -9,7 +9,7 @@ from shapely.geometry import mapping
 from app.core.errors import AppError
 from app.models import Area, Dataset, Project, VectorFeature
 from app.schemas.area import AreaCreate, AreaRead, AreaUpdate
-from app.utils.geometry import area_m2, geometry_bbox_polygon, normalize_to_multipolygon
+from app.utils.geometry import area_m2, geometry_bbox_polygon, normalize_area_to_epsg4326
 
 
 class AreaService:
@@ -126,7 +126,11 @@ class AreaService:
             raise AppError(code="PROJECT_NOT_FOUND", message="Project not found", status_code=404)
 
         try:
-            multipolygon = normalize_to_multipolygon(payload.geometry)
+            multipolygon, original_crs = normalize_area_to_epsg4326(
+                payload.geometry,
+                payload.crs or "EPSG:4326",
+            )
+            metric_area = area_m2(multipolygon)
         except ValueError as exc:
             raise AppError(code="INVALID_GEOMETRY", message=str(exc), status_code=400) from exc
 
@@ -134,8 +138,8 @@ class AreaService:
             project_id=project_id,
             name=payload.name.strip() or "Unnamed area",
             geometry=from_shape(multipolygon, srid=4326),
-            original_crs=payload.crs or "EPSG:4326",
-            area_m2=area_m2(multipolygon),
+            original_crs=original_crs,
+            area_m2=metric_area,
             bbox=from_shape(geometry_bbox_polygon(multipolygon), srid=4326),
         )
         db.add(area)
@@ -157,11 +161,28 @@ class AreaService:
             raise AppError(code="AREA_NOT_FOUND", message="Area not found", status_code=404)
 
         changed = False
-        if payload.name:
+        if payload.name is not None and payload.name.strip():
             area.name = payload.name.strip() or area.name
             changed = True
-        if payload.crs:
-            area.original_crs = payload.crs
+        if payload.crs is not None and payload.geometry is None:
+            raise AppError(
+                code="INVALID_AREA_CRS_UPDATE",
+                message="crs can only be supplied together with replacement geometry",
+                status_code=422,
+            )
+        if payload.geometry is not None:
+            try:
+                multipolygon, original_crs = normalize_area_to_epsg4326(
+                    payload.geometry,
+                    payload.crs or "EPSG:4326",
+                )
+                metric_area = area_m2(multipolygon)
+            except ValueError as exc:
+                raise AppError(code="INVALID_GEOMETRY", message=str(exc), status_code=400) from exc
+            area.geometry = from_shape(multipolygon, srid=4326)
+            area.original_crs = original_crs
+            area.area_m2 = metric_area
+            area.bbox = from_shape(geometry_bbox_polygon(multipolygon), srid=4326)
             changed = True
         if not changed:
             raise AppError(code="NO_CHANGES", message="No updatable fields provided", status_code=422)