--- a/artifacts/src/main/java/org/dive4elements/river/artifacts/states/WQSelect.java	Mon Feb 26 18:10:03 2018 +0100
+++ b/artifacts/src/main/java/org/dive4elements/river/artifacts/states/WQSelect.java	Tue Feb 27 18:06:52 2018 +0100
@@ -30,10 +30,9 @@
 import org.dive4elements.river.model.Wst;
 
 import org.dive4elements.river.artifacts.D4EArtifact;
-import org.dive4elements.river.artifacts.WINFOArtifact;
 
 import org.dive4elements.river.artifacts.access.RangeAccess;
-
+import org.dive4elements.river.artifacts.access.ComputationRangeAccess;
 import org.dive4elements.river.artifacts.model.WstFactory;
 import org.dive4elements.river.artifacts.model.WstValueTable;
 import org.dive4elements.river.artifacts.model.WstValueTableFactory;
@@ -104,8 +103,6 @@
         Boolean isQ = flys.getDataAsBoolean(WQ_MODE);
         Boolean isFree = flys.getDataAsBoolean(WQ_FREE);
 
-        WINFOArtifact winfo = (WINFOArtifact) flys;
-
         Element dataElement = creator.create("data");
         creator.addAttr(dataElement, "name", name, true);
         creator.addAttr(dataElement, "type", type, true);
@@ -116,10 +113,10 @@
         String label;
 
         if (!isQ || isFree) {
-            label = getLabel(winfo, cc, value);
+            label = getLabel(flys, cc, value);
         }
         else {
-            label = getSpecialLabel(winfo, cc, value);
+            label = getSpecialLabel(flys, cc, value);
         }
 
         creator.addAttr(itemElement, "label", label, true);
@@ -131,7 +128,7 @@
 
 
     protected static String getLabel(
-        WINFOArtifact winfo,
+        D4EArtifact winfo,
         CallContext   cc,
         String        raw
     ) {
@@ -167,7 +164,7 @@
 
 
     protected static String getSpecialLabel(
-        WINFOArtifact winfo,
+        D4EArtifact winfo,
         CallContext   cc,
         String        raw
     ) {
@@ -250,12 +247,12 @@
         String      name,
         CallContext context
     ){
-        WINFOArtifact winfo = (WINFOArtifact) artifact;
+        D4EArtifact flys = (D4EArtifact) artifact;
 
-        double[] minmaxW     = determineMinMaxW(winfo);
-        double[] minmaxWFree = determineMinMaxWFree(winfo);
-        double[] minmaxQ     = determineMinMaxQAtGauge(winfo);
-        double[] minmaxQFree = determineMinMaxQ(winfo);
+        double[] minmaxW     = determineMinMaxW(flys);
+        double[] minmaxWFree = determineMinMaxWFree(flys);
+        double[] minmaxQ     = determineMinMaxQAtGauge(flys);
+        double[] minmaxQFree = determineMinMaxQ(flys);
 
         if (name.equals("wq_from")) {
             Element minW = createItem(cr, new String[] {
@@ -400,7 +397,7 @@
      *
      * @return the min and max W values for the current gauge.
      */
-    protected double[] determineMinMaxW(WINFOArtifact winfo) {
+    protected double[] determineMinMaxW(D4EArtifact winfo) {
         log.debug("WQSelect.determineCurrentGauge");
 
         RangeAccess rangeAccess = new RangeAccess(winfo);
@@ -425,22 +422,24 @@
      *
      * @return the min and max W values.
      */
-    protected double[] determineMinMaxWFree(WINFOArtifact winfo) {
+    protected double[] determineMinMaxWFree(D4EArtifact winfo) {
         log.debug("WQSelect.determineMinMaxWFree");
 
         WstValueTable valueTable = WstValueTableFactory.getTable(
                 RiverUtils.getRiver(winfo));
 
+        ComputationRangeAccess access = new ComputationRangeAccess(winfo);
+        
         double[] minmaxW = null;
         if(valueTable != null) {
             double[] km = null;
-            if(new RangeAccess(winfo).isRange()) {
-                km = winfo.getFromToStep();
+            if(access.isRange()) {
+                km = access.getFromToStep();
                 // Use the start km to determine the min max values.
                 minmaxW = valueTable.getMinMaxW(km[0]);
             }
             else {
-                km = winfo.getKms();
+                km = access.getKms();
                 minmaxW = valueTable.getMinMaxW(km[0]);
             }
         }
@@ -459,7 +458,7 @@
      *
      * @return the min and max Q values for the current gauge.
      */
-    protected double[] determineMinMaxQAtGauge(WINFOArtifact winfo) {
+    protected double[] determineMinMaxQAtGauge(D4EArtifact winfo) {
         log.debug("WQSelect.determineMinMaxQAtGauge");
 
         RangeAccess rangeAccess = new RangeAccess(winfo);
@@ -488,21 +487,23 @@
      *
      * @return the min and max Q values for the current kilometer range.
      */
-    protected double[] determineMinMaxQ(WINFOArtifact winfo) {
+    protected double[] determineMinMaxQ(D4EArtifact winfo) {
         log.debug("WQSelect.determineMinMaxQ");
 
         WstValueTable valueTable = WstValueTableFactory.getTable(
                 RiverUtils.getRiver(winfo));
 
+        ComputationRangeAccess access = new ComputationRangeAccess(winfo);
+        
         double[] minmaxQ = null;
         if(valueTable != null) {
             double[] km = null;
-            if(new RangeAccess(winfo).isRange()) {
-                km = winfo.getFromToStep();
+            if(access.isRange()) {
+                km =  new ComputationRangeAccess(winfo).getFromToStep();
                 minmaxQ = valueTable.getMinMaxQ(km[0], km[1], km[2]);
             }
             else {
-                km = winfo.getKms();
+                km = access.getKms();
                 minmaxQ = valueTable.getMinMaxQ(km[0]);
                 for (int i = 1; i < km.length; i++) {
                     double[] tmp = valueTable.getMinMaxQ(km[i]);
@@ -527,7 +528,7 @@
     {
         log.debug("WQSelect.validate");
 
-        WINFOArtifact flys = (WINFOArtifact) artifact;
+        D4EArtifact flys = (D4EArtifact) artifact;
 
         StateData data       = getData(flys, WQ_SELECTION);
         boolean isRange = data != null
@@ -567,7 +568,7 @@
     }
 
 
-    protected boolean validateSingle(WINFOArtifact artifact)
+    protected boolean validateSingle(D4EArtifact artifact)
     throws    IllegalArgumentException
     {
         log.debug("WQSelect.validateSingle");
@@ -623,7 +624,7 @@
     }
 
 
-    protected boolean validateRange(WINFOArtifact artifact)
+    protected boolean validateRange(D4EArtifact artifact)
     throws    IllegalArgumentException
     {
         log.debug("WQSelect.validateRange");
@@ -685,7 +686,7 @@
      * @return true, if everything was fine, otherwise an exception is thrown.
      */
     protected boolean validateGaugeW(
-        WINFOArtifact    artifact,
+        D4EArtifact    artifact,
         double from,
         double to,
         double step)
@@ -711,7 +712,7 @@
      * @return true, if everything was fine, otherwise an exception is thrown.
      */
     protected boolean validateGaugeQ(
-        WINFOArtifact artifact,
+        D4EArtifact artifact,
         double   from,
         double   to,
         double   step)
@@ -737,7 +738,7 @@
      * @return true, if everything was fine, otherwise an exception is thrown.
      */
     protected boolean validateFreeQ(
-        WINFOArtifact artifact,
+        D4EArtifact artifact,
         double   from,
         double   to,
         double   step)
@@ -763,7 +764,7 @@
      * @return true, if everything was fine, otherwise an exception is thrown.
      */
     protected boolean validateFreeW(
-        WINFOArtifact artifact,
+        D4EArtifact artifact,
         double   from,
         double   to,
         double   step)