--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/artifacts/src/main/java/org/dive4elements/river/artifacts/sinfo/tkhcalculation/WaterlevelValuesFinder.java	Tue Mar 13 18:49:33 2018 +0100
@@ -0,0 +1,43 @@
+/** Copyright (C) 2017 by Bundesanstalt für Gewässerkunde
+ * Software engineering by
+ *  Björnsen Beratende Ingenieure GmbH
+ *  Dr. Schumacher Ingenieurbüro für Wasser und Umwelt
+ *
+ * This file is Free Software under the GNU AGPL (>=v3)
+ * and comes with ABSOLUTELY NO WARRANTY! Check out the
+ * documentation coming with Dive4Elements River for details.
+ */
+package org.dive4elements.river.artifacts.sinfo.tkhcalculation;
+
+import org.apache.commons.math.ArgumentOutsideDomainException;
+import org.apache.commons.math.analysis.polynomials.PolynomialSplineFunction;
+import org.dive4elements.river.artifacts.model.WKms;
+import org.dive4elements.river.utils.DoubleUtil;
+
+/**
+ * Abstraction for access to waterlevels by station.
+ *
+ * @author Gernot Belger
+ */
+public class WaterlevelValuesFinder {
+
+    public static WaterlevelValuesFinder fromKms(final WKms wkms) {
+        return new WaterlevelValuesFinder(wkms);
+    }
+
+    private final PolynomialSplineFunction wstInterpolator;
+
+    private WaterlevelValuesFinder(final WKms wkms) {
+        this.wstInterpolator = DoubleUtil.getLinearInterpolator(wkms.allKms(), wkms.allWs());
+    }
+
+    public double getWaterlevel(final double km) {
+        try {
+            return this.wstInterpolator.value(km);
+        }
+        catch (final ArgumentOutsideDomainException e) {
+            e.printStackTrace();
+            return Double.NaN;
+        }
+    }
+}
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