--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gnv-artifacts/src/main/java/de/intevation/gnv/math/Point2d.java	Fri Sep 28 12:13:53 2012 +0200
@@ -0,0 +1,199 @@
+package de.intevation.gnv.math;
+
+import com.vividsolutions.jts.geom.Coordinate;
+import com.vividsolutions.jts.geom.Envelope;
+
+import java.util.Comparator;
+
+import org.apache.log4j.Logger;
+
+/**
+ *  @author Sascha L. Teichmann (sascha.teichmann@intevation.de)
+ */
+public class Point2d
+extends      Coordinate
+{
+    private static Logger log = Logger.getLogger(Point2d.class);
+
+    public static final double EPSILON = 1e-3d;
+
+    public static final Comparator X_COMPARATOR = new Comparator() {
+        public int compare(Object a, Object b) {
+            double xa = ((Coordinate)a).x;
+            double xb = ((Coordinate)b).x;
+            if (xa < xb) return -1;
+            if (xa > xb) return +1;
+            return 0;
+        }
+    };
+
+    public static final Comparator Y_COMPARATOR = new Comparator() {
+        public int compare(Object a, Object b) {
+            double ya = ((Coordinate)a).y;
+            double yb = ((Coordinate)b).y;
+            if (ya < yb) return -1;
+            if (ya > yb) return +1;
+            return 0;
+        }
+    };
+
+    public static class InverseL1Comparator
+    implements          Comparator
+    {
+        private Point2d ref;
+
+        public InverseL1Comparator(Point2d ref) {
+            this.ref = ref;
+        }
+
+        public int compare(Object a, Object b) {
+            Point2d pa = (Point2d)a;
+            Point2d pb = (Point2d)b;
+            double da = ref.L1(pa);
+            double db = ref.L1(pb);
+            if (da < db) return -1;
+            if (da > db) return +1;
+            return 0;
+        }
+    } // class InverseL1Comparator
+
+    public int i;
+    public int j;
+
+    public Point2d() {
+    }
+
+    public Point2d(double x, double y) {
+        super(x, y);
+    }
+
+    public Point2d(double x, double y, int i, int j) {
+        super(x, y);
+        this.i = i;
+        this.j = j;
+    }
+
+    public Point2d(double x, double y, double z, int i, int j) {
+        super(x, y, z);
+        this.i = i;
+        this.j = j;
+    }
+
+
+    public double L1(Point2d other) {
+        return L1(this, other);
+    }
+
+    public static double L1(Coordinate a, Coordinate b) {
+        return Math.abs(a.x - b.x) + Math.abs(a.y - b.y);
+    }
+
+    public Envelope envelope() {
+        return envelope(EPSILON);
+    }
+
+    public Envelope envelope(double epsilon) {
+        return new Envelope(
+            x-epsilon, x+epsilon,
+            y-epsilon, y+epsilon);
+    }
+
+    public boolean hasIGap(Point2d other) {
+        return Math.abs(i - other.i) > 1;
+    }
+
+    public boolean hasJGap(Point2d other) {
+        return Math.abs(j - other.j) > 1;
+    }
+
+    public Point2d extrapolate(double t, Point2d other) {
+        if (other == null) {
+            return null;
+        }
+        Point2d p = newPoint();
+        p.x = t*(other.x - x) + x;
+        p.y = t*(other.y - y) + y;
+        return p;
+    }
+
+    public Point2d newPoint() {
+        return new Point2d(0d, 0d);
+    }
+
+    public Point2d newPoint(double x, double y) {
+        return new Point2d(x, y);
+    }
+
+    public void inverseDistanceWeighting(Point2d [] ps) {
+
+        double sum = 0d;
+
+        double [] d = new double[ps.length];
+
+        for (int i = 0; i < ps.length; ++i) {
+            Point2d p = ps[i];
+            if (p != null) {
+                double di = distance(p);
+                if (di < 1e-5d) { z = p.z; return; }
+                di = 1d/di;
+                d[i] = di;
+                sum += di;
+            }
+        }
+
+        if (sum == 0d) {
+            return;
+        }
+
+        double v = 0d;
+
+        for (int i = 0; i < ps.length; ++i) {
+            Point2d p = ps[i];
+            if (p != null) {
+                v += p.z*d[i];
+            }
+        }
+        z = v/sum;
+    }
+
+    public static Point2d average(Point2d [] ps) {
+
+        Point2d p = null;
+        int count = 0;
+
+        for (int i = 0; i < ps.length; ++i) {
+            Point2d t = ps[i];
+            if (t != null) {
+                ++count;
+                if (p == null) {
+                    p = t.newPoint(t.x, t.y);
+                }
+                else {
+                    p.x += t.x;
+                    p.y += t.y;
+                }
+            }
+        }
+
+        if (p != null) {
+            double s = 1d/count;
+            p.x *= s;
+            p.y *= s;
+        }
+
+        return p;
+    }
+
+    public boolean near(Point2d [] ps) {
+
+        for (int i = 0; i < ps.length; ++i) {
+            Point2d p = ps[i];
+            if (p != null && distance(p) > EPSILON) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8: