--- a/flys-artifacts/src/main/java/de/intevation/flys/artifacts/states/WDifferencesState.java	Fri Sep 09 10:13:22 2011 +0000
+++ b/flys-artifacts/src/main/java/de/intevation/flys/artifacts/states/WDifferencesState.java	Fri Sep 09 12:29:28 2011 +0000
@@ -74,18 +74,22 @@
             logger.warn("One of the artifacts (2) for diff calculation could not be loaded");
         }
         WKms wkms = null;
+        String facetName = "diff ()";
 
         if (flys1 != null && flys2 != null) {
+            // TODO also check size.
+            // TODO also need index of wqkms.
             WQKms[] minuend = (WQKms[]) flys1.getWaterlevelData().getData();
             WQKms[] subtrahend = (WQKms[]) flys2.getWaterlevelData().getData();
             wkms = WKmsOperation.SUBTRACTION.operate(minuend[0], subtrahend[0]);
+            facetName = "W ("+minuend[0].getName() + ") - W (" + subtrahend[0].getName()+")";
             logger.warn("Did a WKMSSubtraction");
         }
 
         if (facets != null) {
             // TODO: pass computetype and state id.
             //, ComputeType.ADVANCE, getID(), hash));
-            facets.add(new DataFacet(W_DIFFERENCES, "wdiff data"));
+            facets.add(new DataFacet(W_DIFFERENCES, facetName));
         }
         else {
             logger.debug("Not adding facets in WDifferencesState.");