Index: src/uk/me/parabola/mkgmap/reader/osm/MultiPolygonRelation.java
===================================================================
--- src/uk/me/parabola/mkgmap/reader/osm/MultiPolygonRelation.java	(Revision 1457)
+++ src/uk/me/parabola/mkgmap/reader/osm/MultiPolygonRelation.java	(Arbeitskopie)
@@ -349,44 +348,39 @@
 				unfinishedRings.andNot(innerIndexes);
 
 				// now construct the outer polygon with its holes
-				for (Way innerRing : innerRings) {
-					int[] insert = findCpa(outerRing.getPoints(), innerRing
-							.getPoints());
-					if (insert[0] >= 0 && insert[1] >= 0) {
-						insertPoints(outerRing, innerRing, insert[0], insert[1]);
-					}
-				}
-
-				// set the tags of the outer ring
-				// does the multipolygon itself have any tags?
-				boolean validTagFound = false;
-				for (Map.Entry<String, String> tagEntry : getEntryIteratable()) {
+				List<Way> decomposition = PolygonDecomposer.decompose(outerRing, innerRings);
+				myWayMap.remove(outerRing.getId());
+				for (Way way : decomposition) {
+				    // set the tags of the outer ring
+				    // does the multipolygon itself have any tags?
+				    boolean validTagFound = false;
+				    for (Map.Entry<String, String> tagEntry : getEntryIteratable()) {
 					if (relationTags.contains(tagEntry.getKey())) {
-						validTagFound = true;
-						break;
+					    validTagFound = true;
+					    break;
 					}
-				}
+				    }
 
-				if (validTagFound) {
+				    if (validTagFound) {
 					// the multipolygon contains tags that overwhelm the tags
 					// out the outer ring
-					outerRing.copyTags(this);
-				} else {
+					way.copyTags(this);
+				    } else {
 					// the multipolygon does not contain any relevant tag
 					// use the segments of the outer ring and merge the tags
 					for (Way outerRingSegment : outerRing.getOriginalWays()) {
-						// TODO uuh, this is bad => the last of the outer ring
-						// segments win
-						// => any better idea?
-						for (Map.Entry<String, String> outSegmentTag : outerRingSegment
-								.getEntryIteratable()) {
-							outerRing.addTag(outSegmentTag.getKey(),
-									outSegmentTag.getValue());
-						}
+					    // TODO uuh, this is bad => the last of the outer ring
+					    // segments win
+					    // => any better idea?
+					    for (Map.Entry<String, String> outSegmentTag : outerRingSegment
+						     .getEntryIteratable()) {
+						way.addTag(outSegmentTag.getKey(),
+								 outSegmentTag.getValue());
+					    }
 					}
+				    }
+				    polygonResults.add(way);
 				}
-
-				polygonResults.add(outerRing);
 			}
 		}
 
@@ -601,11 +595,11 @@
 	 * This is a helper class that stores that gives access to the original segments
 	 * of a joined way.
 	 */
-	private static class JoinedWay extends Way {
+       private static class JoinedWay extends Way {
 		private final List<Way> originalWays;
 
 		public JoinedWay(Way originalWay) {
-			super(-originalWay.getId(), new ArrayList<Coord>(originalWay
+			super(originalWay.getId(), new ArrayList<Coord>(originalWay
 					.getPoints()));
 			this.originalWays = new ArrayList<Way>();
 			this.originalWays.add(originalWay);
Index: src/uk/me/parabola/mkgmap/reader/osm/Way.java
===================================================================
--- src/uk/me/parabola/mkgmap/reader/osm/Way.java	(Revision 1457)
+++ src/uk/me/parabola/mkgmap/reader/osm/Way.java	(Arbeitskopie)
@@ -91,7 +91,7 @@
 
 	public void reverse() {
 		int numPoints = points.size();
-		for(int i = 0; i < numPoints/2; ++i) {
+		for (int i = 0; i < numPoints/2; ++i) {
 			Coord t = points.get(i);
 			points.set(i, points.get(numPoints - 1 - i));
 			points.set(numPoints - 1 - i, t);
@@ -102,7 +102,21 @@
 		return !points.isEmpty() && points.get(0).equals(points.get(points.size()-1));
 	}
 
+        /** Check wether a (closed) way is ordered clockwise.
+	 *  @return true, if the way is ordered clockwise.
+	 */
+        public boolean isClockwise() {
+	    double sum = 0;
+	    int numPoints = points.size();
+	    for (int i=0; i < numPoints-1; i++) {
+		Coord p1 = points.get(i);
+		Coord p2 = points.get(i+1);
+		sum += p2.getLongitude()*p1.getLatitude() - p1.getLongitude()*p2.getLatitude();
+	    }
+	    return sum > 0;
+	}
+
 	/**
 	 * A simple representation of this way.
 	 * @return A string with the name and start point