hotfix to be debugged later
@@ -375,6 +375,7 @@ class AltitudeArea(LevelGeometryMixin, models.Model):
areas_by_altitude = {}
for tmpid in level_areas.get(level, []):
area = areas[tmpid]
+ if area.geometry: # todo: how can this be None?
areas_by_altitude.setdefault(area.altitude, []).append(area.geometry)
areas_by_altitude = {altitude: [unary_union(alt_areas)]
for altitude, alt_areas in areas_by_altitude.items()}
