--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/flys-artifacts/src/main/java/org/dive4elements/river/artifacts/model/minfo/SedimentDensity.java	Thu Apr 25 12:06:39 2013 +0200
@@ -0,0 +1,158 @@
+package org.dive4elements.river.artifacts.model.minfo;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.log4j.Logger;
+
+
+public class SedimentDensity
+{
+    private static final Logger logger = Logger
+        .getLogger(SedimentDensity.class);
+
+    private Map<Integer, List<SedimentDensityValue>> densities;
+    private List<Integer> years;
+
+    public SedimentDensity() {
+        this.densities = new HashMap<Integer, List<SedimentDensityValue>>();
+        this.years = new ArrayList<Integer>();
+    }
+
+    public Map<Integer, List<SedimentDensityValue>> getDensities() {
+        return densities;
+    }
+
+    public void setDensities(Map<Integer, List<SedimentDensityValue>> densities) {
+        this.densities = densities;
+    }
+
+    public void addDensity(double km, double density, int year) {
+        logger.debug("adding " + year);
+        if (this.densities.containsKey(year)) {
+            List<SedimentDensityValue> list = this.densities.get(year);
+            list.add(new SedimentDensityValue(km, density, year));
+        }
+        else {
+            List<SedimentDensityValue> list =
+                new ArrayList<SedimentDensityValue>();
+            list.add(new SedimentDensityValue(km, density, year));
+            densities.put(year, list);
+        }
+        if (!this.years.contains(new Integer(year))) {
+            logger.debug("new year");
+            years.add(new Integer(year));
+        }
+    }
+
+    public List<Integer> getYears() {
+        return years;
+    }
+
+    public void setYears(List<Integer> years) {
+        this.years = years;
+    }
+
+    public double getDensity(double km, int year) {
+        Collections.sort(this.years);
+        if (this.years.size() == 1) {
+            return getDensityAtKm(densities.get(year), km);
+        }
+        else {
+            for (int i = 0; i < years.size() -1; i++) {
+                int y1 = years.get(i);
+                int y2 = years.get(i + 1);
+                int mid = Math.round((y1 + y2) / 2);
+                if (year < mid) {
+                    return getDensityAtKm(densities.get(y1), km);
+                }
+                else if (i == years.size() -1) {
+                    continue;
+                }
+                else {
+                    return getDensityAtKm(densities.get(y2), km);
+                }
+            }
+        }
+        return 1.8d;
+    }
+
+    private double getDensityAtKm(
+        List<SedimentDensityValue> values,
+        double km
+    ) {
+        boolean found = true;
+        SedimentDensityValue prev = null;
+        SedimentDensityValue next = null;
+        for (SedimentDensityValue sdv: values) {
+logger.debug("year: " + sdv.getYear());
+            if (sdv.getKm() == km) {
+                prev = sdv;
+                found = true;
+                break;
+            }
+            if (sdv.getKm() > km) {
+                next = sdv;
+                break;
+            }
+            prev = sdv;
+        }
+        if (found) {
+            return prev.getDensity();
+        }
+        else {
+            return spline(prev, next, km);
+        }
+    }
+
+    private double spline(
+        SedimentDensityValue prev,
+        SedimentDensityValue next,
+        double km
+    ) {
+        double lower = prev.getKm();
+        double upper = next.getKm();
+        double upperDensity = next.getDensity();
+        double lowerDensity = prev.getDensity();
+
+        double m =(upperDensity - lowerDensity)/(upper - lower) * km;
+        double b = lowerDensity -
+            ((upperDensity - lowerDensity)/(upper - lower) * lower);
+        return (m * km) + b;
+    }
+
+    public void cleanUp() {
+        Set<Integer> keys = densities.keySet();
+        for (Integer key : keys) {
+            List<SedimentDensityValue> list = densities.get(key);
+            if (list.size() == 0) {
+                return;
+            }
+            List<SedimentDensityValue> cleaned =
+                new ArrayList<SedimentDensityValue>();
+            double prevkm = list.get(0).getKm();
+            int counter = 0;
+            double sum = 0d;
+            for (SedimentDensityValue value : list) {
+                if (value.getKm() == prevkm) {
+                    sum += value.getDensity();
+                    counter++;
+                }
+                else {
+                    cleaned.add(new SedimentDensityValue(
+                        prevkm,
+                        sum / counter,
+                        value.getYear()));
+                    sum = value.getDensity();
+                    counter = 1;
+                }
+                prevkm = value.getKm();
+            }
+            this.densities.put(key, cleaned);
+        }
+    }
+}