--- a/gnv-artifacts/ChangeLog	Wed Dec 23 09:45:40 2009 +0000
+++ b/gnv-artifacts/ChangeLog	Wed Dec 23 12:20:25 2009 +0000
@@ -1,7 +1,43 @@
+2009-12-23	Sascha L. Teichmann	<sascha.teichmann@intevation.de>
+
+	* src/main/java/de/intevation/gnv/math/XYColumn.java: Added a method
+	  prepare() which generates an continues interpolator for the
+	  given z values. if only one value is given a constant function
+	  is assumed. If the larger z-value is below zero the
+	  next lower value is supplemented at zero. Symmetrically 
+	  if the lowest z-value is above the depth at the given point
+	  the lowest value is repeated at depth. This should guarantee
+	  that the gradient is vansihing towards the surface and the
+	  bottom of the ocean.
+
+	  If after the supplementation there are less than three points
+	  a linear interpolation is performed. If there are more than three
+	  points a higher degree interpolation is used instead. This defaults
+	  to a cubic spline interpolation. Overwrite the getInterpolator()
+	  function to replace this behavior.
+	  
+	* src/main/java/de/intevation/gnv/math/ConstantFunction.java: New.
+	  Constant function used in interpolation.
+
+	* src/main/java/de/intevation/gnv/math/LinearFunction.java: Added
+	  an inner class Univariate which fits into the interpolation
+	  framework.
+
+	* src/main/java/de/intevation/gnv/math/HeightValue.java: Sort
+	  z-Values in descending order because we are below zero.
+
+	* src/main/java/de/intevation/gnv/math/XYDepth.java: New. Interface
+	  to figure out the depth (negative values below surface) for
+	  a given coordinate. TODO: Implement this by query the DEM grid
+	  of the ocean.
+
+	* src/main/java/de/intevation/gnv/math/AttributedXYColumns.java: Added
+	  authors.
+
 2009-12-23	Sascha L. Teichmann	<sascha.teichmann@intevation.de>
 
 	* src/main/java/de/intevation/gnv/state/profile/verticalcrosssection/VerticalCrossSectionOutputState.java:
-	  When preprocessing database data only dissamble WKT points if we
+	  When preprocessing database data only dissemble WKT points if we
 	  have to.
 	  Read z values as double value now.
 	  Commented out CSV export because it takes the database data