/// <summary>
/// Chen and Guevara 77
/// </summary>
/// <param name="numberOfPoints"></param>
/// <returns></returns>
public AttributedPointCollection SelectPointsBaesdOnCAG(int numberOfPoints)
{
int numberOfRow = this.NumberOfRows;
int numberOfColumns = this.NumberOfColumns;
IndexValue <double>[] significanceValues = new IndexValue <double> [numberOfRow * numberOfColumns];
for (int i = 1; i < numberOfRow - 1; i++)
{
for (int j = 1; j < numberOfColumns - 1; j++)
{
double first = CalculateSecondDifference(i, j, RasterDirection.EastWest);
double second = CalculateSecondDifference(i, j, RasterDirection.SouthNorth);
double third = CalculateSecondDifference(i, j, RasterDirection.NorthernWestSouthernEast);
double fourth = CalculateSecondDifference(i, j, RasterDirection.SouthernWestNorthernEast);
significanceValues[i * numberOfColumns + j] =
new IndexValue <double>(i * numberOfColumns + j, first + second + third + fourth);
}
}
IndexValue <double>[] sortedSignificanceValues = SortAlgorithm.Heapsort <IndexValue <double> >(significanceValues, SortDirection.Ascending);
AttributedPointCollection irregularPoints = new AttributedPointCollection();
for (int i = 0; i < numberOfPoints; i++)
{
int row = (int)Math.Floor((double)sortedSignificanceValues[i].Index / numberOfColumns);
int column = sortedSignificanceValues[i].Index % numberOfColumns;
irregularPoints.Add(this.GetPoint(row, column));
}
//AddBorder
irregularPoints.Add(this.LowerLeft);
irregularPoints.Add(this.LoweRight);
irregularPoints.Add(this.UpperLeft);
irregularPoints.Add(this.UppeRight);
return(irregularPoints);
}
public IrregularDtm(AttributedPointCollection collection)
{
this.collection = collection;
//PointCollection c = new PointCollection();
//for (int i = 0; i < collection.Count; i++)
//{
// c.Add(new Point(collection[i].X, collection[i].Y));
//}
this.triangulation = new DelaunayTriangulation(this.collection);
currenTriangle = triangulation.triangles[0];
}
public IrregularDtm(double[] east, double[] north, double[] value)
{
try
{
this.collection = new AttributedPointCollection(new List <double>(east),
new List <double>(north),
new List <double>(value));
triangulation = new DelaunayTriangulation(collection);
currenTriangle = triangulation.triangles[0];
}
catch (Exception ex)
{
throw ex;
}
}
public AttributedPointCollection SelectPointsBasedOnLi(double threshold)
{
int numberOfRow = this.NumberOfRows;
int numberOfColumns = this.NumberOfColumns;
AttributedPointCollection irregularPoints = new AttributedPointCollection();
Matrix values = this.values.Clone();
for (int i = 1; i < numberOfRow - 1; i++)
{
for (int j = 1; j < numberOfColumns - 1; j++)
{
double firstDifference = values[i, j] - ((values[i, j - 1] + values[i, j + 1]) / 2);
double secondDifference = values[i, j] - ((values[i - 1, j] + values[i + 1, j]) / 2);
double thirdDifference = values[i, j] - ((values[i + 1, j - 1] + values[i - 1, j + 1]) / 2);
double fourthDifference = values[i, j] - ((values[i - 1, j - 1] + values[i + 1, j + 1]) / 2);
if ((Math.Abs(firstDifference) + Math.Abs(secondDifference) + Math.Abs(thirdDifference) + Math.Abs(fourthDifference)) / 4 > threshold)
{
irregularPoints.Add(this.GetPoint(i, j));
}
else
{
values[i, j] = (4 * values[i, j] - firstDifference - secondDifference - thirdDifference - fourthDifference) / 4;
}
}
}
//AddBorder
irregularPoints.Add(this.LowerLeft);
irregularPoints.Add(this.LoweRight);
irregularPoints.Add(this.UpperLeft);
irregularPoints.Add(this.UppeRight);
return(irregularPoints);
}
public IrregularDtm ToIrregularDtmBasedOnLi(double threshold)
{
AttributedPointCollection irregularPoints = SelectPointsBasedOnLi(threshold);
return(new IrregularDtm(irregularPoints));
}
public IrregularDtm ToIrregularDtmBaesdOnCAG(int numberOfPoints)
{
AttributedPointCollection irregularPoints = SelectPointsBaesdOnCAG(numberOfPoints);
return(new IrregularDtm(irregularPoints));
}
