--- a/artifacts/src/main/java/org/dive4elements/river/artifacts/model/AreaFacet.java	Thu Dec 19 18:36:00 2013 +0100
+++ b/artifacts/src/main/java/org/dive4elements/river/artifacts/model/AreaFacet.java	Fri Dec 20 12:40:08 2013 +0100
@@ -64,7 +64,8 @@
         AreaArtifact artifact = (AreaArtifact) art;
         Object lowerData      = null;
         Object upperData      = null;
-        String stemFacetName  = null;
+        String lowerFacetName = null;
+        String upperFacetName = null;
 
         List<DataProvider> providers = context.
             getDataProvider(artifact.getLowerDPKey());
@@ -77,7 +78,7 @@
                 artifact.getLowerDPKey(), null, context);
             logger.debug("'Lower' data provider key for area [" +
                 artifact.getLowerDPKey() + "]");
-            stemFacetName = artifact.getLowerDPKey().split(":")[1];
+            lowerFacetName = artifact.getLowerDPKey().split(":")[1];
         }
 
         providers = context.getDataProvider(artifact.getUpperDPKey());
@@ -90,16 +91,14 @@
                 artifact.getUpperDPKey(), null, context);
             logger.debug("'Upper' data provider key for area [" +
                 artifact.getUpperDPKey() + "]");
-            if (stemFacetName == null) {
-                stemFacetName = artifact.getUpperDPKey().split(":")[1];
-            }
+            upperFacetName = artifact.getUpperDPKey().split(":")[1];
         }
 
         if (upperData == null && lowerData == null) {
             logger.warn("Not given 'upper' and 'lower' for area");
         }
 
-        return new Data(stemFacetName, lowerData, upperData,
+        return new Data(upperFacetName, lowerFacetName, lowerData, upperData,
             Boolean.valueOf(artifact.getPaintBetween()));
     }
 
@@ -113,24 +112,28 @@
     }
 
     /** Result data bundle. */
-    public class Data {
-        protected String  rootFacetName;
+    public static class Data {
+        protected String  upperFacetName;
+        protected String  lowerFacetName;
         protected Object  upperData;
         protected Object  lowerData;
         protected boolean doPaintBetween;
 
         /** Create a new result data bundle. */
-        public Data(String rootName, Object low, Object up, boolean between) {
-            this.rootFacetName  = rootName;
+        public Data(String upperFacetName, String lowerFacetName, Object low, Object up, boolean between) {
             this.lowerData      = low;
             this.upperData      = up;
             this.doPaintBetween = between;
+            this.lowerFacetName = lowerFacetName;
+            this.upperFacetName = upperFacetName;
         }
 
-        /** Get name of a facet that is involved in area generation
-         * to induce type (e.g. longitudinal_section.w -> "W over km"). */
-        public String getRootFacetName() {
-            return this.rootFacetName;
+        public String getLowerFacetName() {
+            return this.lowerFacetName;
+        }
+
+        public String getUpperFacetName() {
+            return this.upperFacetName;
         }
 
         /** Get data for 'upper' curve of area. */