private static final Collection<MapArea> createAreasForSimpleMultipolygon(
OSMRelation relation, Map<OSMNode, MapNode> nodeMap) {
assert isSimpleMultipolygon(relation);
OSMElement tagSource = null;
List<MapNode> outerNodes = null;
List<List<MapNode>> holes = new ArrayList<List<MapNode>>();
for (OSMMember member : relation.relationMembers) {
if (member.member instanceof OSMWay) {