/// <summary>
///
/// </summary>
/// <param name="geom"></param>
/// <returns></returns>
private static ICoordinate[] ExtractCoordinates(IGeometry geom)
{
UniqueCoordinateArrayFilter filter = new UniqueCoordinateArrayFilter();
geom.Apply(filter);
return(filter.Coordinates);
}
public void TestFilter()
{
var g = Read("MULTIPOINT(10 10, 20 20, 30 30, 20 20, 10 10)");
var f = new UniqueCoordinateArrayFilter();
g.Apply(f);
Assert.That(f.Coordinates.Length, Is.EqualTo(3));
Assert.That(f.Coordinates[0], Is.EqualTo(new Coordinate(10, 10)));
Assert.That(f.Coordinates[1], Is.EqualTo(new Coordinate(20, 20)));
Assert.That(f.Coordinates[2], Is.EqualTo(new Coordinate(30, 30)));
}
public void testUniqueCoordinateArrayFilter()
{
var g = reader.Read(
"MULTIPOINT(10 10, 20 20, 30 30, 20 20, 10 10)");
var f = new UniqueCoordinateArrayFilter();
g.Apply(f);
Assert.AreEqual(3, f.Coordinates.Length);
Assert.AreEqual(new Coordinate(10, 10), f.Coordinates[0]);
Assert.AreEqual(new Coordinate(20, 20), f.Coordinates[1]);
Assert.AreEqual(new Coordinate(30, 30), f.Coordinates[2]);
}
/// <summary>
/// Gets the convex hull for the given geometry.
/// </summary>
/// <param name="geometry"></param>
/// <returns></returns>
public Geometry GetConvexHull(Geometry geometry)
{
this._geometry = geometry;
UniqueCoordinateArrayFilter filter = new UniqueCoordinateArrayFilter();
geometry.Apply(filter);
Coordinates pts = filter.GetCoordinates();
if (pts.Count == 0)
{
return(new GeometryCollection(new Geometry[] {},
geometry.PrecisionModel, geometry.GetSRID()));
}
if (pts.Count == 1)
{
return(new Point(pts[0], geometry.PrecisionModel, geometry.GetSRID()));
}
if (pts.Count == 2)
{
return(new LineString(pts, geometry.PrecisionModel, geometry.GetSRID()));
}
// sort points for Graham scan.
Coordinates pspts;
if (pts.Count > 10)
{
//Probably should be somewhere between 50 and 100?
Coordinates rpts = Reduce(pts);
pspts = PreSort(rpts);
}
else
{
pspts = PreSort(pts);
}
// Use Graham scan to find convex hull.
Stack cHS = GrahamScan(pspts);
// Convert stack to an array.
Coordinates cH = ToCoordinateArray(cHS);
// Convert array to linear ring.
//awcreturn lineOrPolygon(cH);
return(LineOrPolygon(cH));
}
/// <summary>
/// Create a new convex hull construction for the input <see cref="Coordinate" /> array.
/// </summary>
/// <param name="pts"></param>
/// <param name="geomFactory"></param>
public ConvexHull(Coordinate[] pts, IGeometryFactory geomFactory)
{
// _inputPts = pts;
_inputPts = UniqueCoordinateArrayFilter.FilterCoordinates(pts);
_geomFactory = geomFactory;
}
