--- a/gnv-artifacts/src/main/java/de/intevation/gnv/math/Interpolation2D.java	Thu Dec 17 18:56:03 2009 +0000
+++ b/gnv-artifacts/src/main/java/de/intevation/gnv/math/Interpolation2D.java	Mon Dec 21 13:49:49 2009 +0000
@@ -20,7 +20,7 @@
     private static Logger log = Logger.getLogger(Interpolation2D.class);
 
     public interface Consumer {
-        void interpolated(Coordinate point);
+        void interpolated(Coordinate point, boolean success);
     } // interface Consumer
 
     private Interpolation2D() {
@@ -38,8 +38,10 @@
         int N = path.size();
         int M = points.size();
 
-        log.debug("Size of path: " + N);
-        log.debug("Size of points: " + M);
+        if (log.isDebugEnabled()) {
+            log.debug("Size of path: " + N);
+            log.debug("Size of points: " + M);
+        }
 
         if (M < 1 || N < 2) { // nothing to do
             return;
@@ -70,7 +72,7 @@
             }
         }
 
-        dxMax = dxMax + 1e-5d;
+        dxMax += 1e-5d;
 
         map.clear();
 
@@ -97,11 +99,13 @@
             }
         }
 
-        dyMax = dyMax + 1e-5d;
+        dyMax += 1e-5d;
 
         map = null;
 
-        log.debug("buffer size: " + dxMax + " / " + dyMax);
+        if (log.isDebugEnabled()) {
+            log.debug("buffer size: " + dxMax + " / " + dyMax);
+        }
 
         // put into spatial index to speed up finding neighbors.
         Quadtree spatialIndex = new Quadtree();
@@ -187,15 +191,19 @@
                     y1, z1,
                     y2, z2,
                     center.y);
-                consumer.interpolated(center);
+                consumer.interpolated(center, true);
                 ++interpolations;
             }
             else {
+                consumer.interpolated(center, false);
                 ++missedInterpolations;
             }
         }
 
-        log.debug("interpolations: " + interpolations + " / " + missedInterpolations);
+        if (log.isDebugEnabled()) {
+            log.debug("interpolations: " + 
+                interpolations + " / " + missedInterpolations);
+        }
     }
 
     public static final double interpolate(