public void LineAlgorithmsCentroidTest()
{
// valid lines
Assert.AreEqual(new Coordinate(4.5, 6.5), LineAlgorithms.Centroid(new Coordinate(2, 5), new Coordinate(7, 8)));
Assert.AreEqual(new Coordinate(5, 51), LineAlgorithms.Centroid(new BasicLineString(new[] { new Coordinate(5, 2), new Coordinate(5, 100) })));
// invalid line
Assert.IsFalse(LineAlgorithms.Centroid(new Coordinate(Double.NaN, 5), new Coordinate(7, 8)).IsValid);
// valid line string
List <Coordinate> lineString = new List <Coordinate>
{
new Coordinate(1, 1), new Coordinate(1, 3),
new Coordinate(1, 7)
};
Assert.AreEqual(new Coordinate(1, 4), LineAlgorithms.Centroid(lineString));
// valid lines with fixed precision
PrecisionModel precision = new PrecisionModel(0.001);
Assert.AreEqual(new Coordinate(22000, 19000), LineAlgorithms.Centroid(new Coordinate(23000, 16000), new Coordinate(20000, 22000), precision));
Assert.AreEqual(new Coordinate(434898000, 461826000), LineAlgorithms.Centroid(new Coordinate(864325000, 96041000), new Coordinate(5470000, 827611000), precision));
// valid lines at given fixed precision
Assert.AreEqual(new Coordinate(22000, 19000), LineAlgorithms.Centroid(new Coordinate(23654, 16412), new Coordinate(19530, 22009), precision));
Assert.AreEqual(new Coordinate(434898000, 461826000), LineAlgorithms.Centroid(new Coordinate(864325203, 96041202), new Coordinate(5470432, 827611534), precision));
}
/// <summary>
/// Partitions a polygon by triangles.
/// </summary>
public void Compute()
{
// source: http://www.codeproject.com/Articles/8238/Polygon-Triangulation-in-C
_result = new List <Coordinate[]>();
IList <Coordinate> shell = new List <Coordinate>(_shell);
IList <Coordinate> nextShell = new List <Coordinate>(shell);
Coordinate[] triangle;
Int32 coordinateCount = shell.Count - 1;
Int32 coordinateIndex = 1;
while (shell.Count != 4)
{
Coordinate centroid = LineAlgorithms.Centroid(shell[(shell.Count + coordinateIndex - 1) % coordinateCount],
shell[(shell.Count + coordinateIndex + 1) % coordinateCount], PrecisionModel);
nextShell.Remove(nextShell[coordinateIndex]);
if (WindingNumberAlgorithm.IsInsidePolygon(shell, centroid, PrecisionModel) && !ShamosHoeyAlgorithm.Intersects(nextShell, PrecisionModel))
{
triangle = new Coordinate[3]
{
shell[(coordinateCount + coordinateIndex - 1) % coordinateCount],
shell[coordinateIndex],
shell[(coordinateCount + coordinateIndex + 1) % coordinateCount]
};
_result.Add(triangle);
shell.Remove(shell[coordinateIndex]);
coordinateIndex = 1;
coordinateCount--;
}
else
{
coordinateIndex = (coordinateIndex + 1) % (shell.Count - 1);
nextShell = new List <Coordinate>(shell);
}
}
triangle = new Coordinate[3] {
shell[0], shell[1], shell[2]
};
_result.Add(triangle);
_hasResult = true;
}
/// <summary>
/// Partitions a polygon by triangles.
/// </summary>
public void Compute()
{
this.result = new List <Coordinate[]>();
List <Coordinate> shell = new List <Coordinate>(this.Source);
List <Coordinate> nextShell = new List <Coordinate>(this.Source);
Coordinate[] triangle;
Int32 coordinateCount = shell.Count - 1;
Int32 coordinateIndex = 1;
while (shell.Count != 4)
{
Coordinate centroid = LineAlgorithms.Centroid(shell[(shell.Count + coordinateIndex - 1) % coordinateCount], shell[(shell.Count + coordinateIndex + 1) % coordinateCount], this.PrecisionModel);
nextShell.Remove(nextShell[coordinateIndex]);
if (!WindingNumberAlgorithm.InExterior(shell, centroid, this.PrecisionModel) && !ShamosHoeyAlgorithm.Intersects(nextShell, this.PrecisionModel))
{
triangle = new Coordinate[3]
{
shell[(coordinateCount + coordinateIndex - 1) % coordinateCount],
shell[coordinateIndex],
shell[(coordinateCount + coordinateIndex + 1) % coordinateCount]
};
this.result.Add(triangle);
shell.Remove(shell[coordinateIndex]);
coordinateIndex = 1;
coordinateCount--;
}
else
{
coordinateIndex = (coordinateIndex + 1) % (shell.Count - 1);
nextShell = new List <Coordinate>(shell);
}
}
triangle = new Coordinate[3] {
shell[0], shell[1], shell[2]
};
this.result.Add(triangle);
this.hasResult = true;
}