--- a/flys-artifacts/src/main/java/de/intevation/flys/exports/XYChartGenerator.java	Tue Dec 06 10:26:07 2011 +0000
+++ b/flys-artifacts/src/main/java/de/intevation/flys/exports/XYChartGenerator.java	Tue Dec 06 10:38:32 2011 +0000
@@ -78,6 +78,12 @@
 
         /** Merge (or create given range with range so far (if any). */
         private void mergeRanges(Range subRange) {
+            // Avoid merging NaNs, as they take min/max place forever.
+            if (subRange == null ||
+                Double.isNaN(subRange.getLowerBound()) ||
+                Double.isNaN(subRange.getUpperBound())) {
+                return;
+            }
             if (range == null) {
                 range = subRange;
                 return;
@@ -93,11 +99,6 @@
 
         /** Adjust range to include given dataset. */
         public void includeYRange(XYSeries dataset) {
-            // Avoid merging NaNs, as they take min/max place forever.
-            if (Double.isNaN(dataset.getMinY()) ||
-                Double.isNaN(dataset.getMaxY())) {
-                return;
-            }
             mergeRanges(new Range(dataset.getMinY(), dataset.getMaxY()));
         }
 
@@ -368,6 +369,12 @@
      */
     private void combineXRanges(Range range, int index) {
 
+        if (range == null
+            || Double.isNaN(range.getLowerBound())
+            || Double.isNaN(range.getUpperBound())) {
+            return;
+        }
+
         Range old = xRanges.get(index);
 
         if (old != null) {