用NetTopologySuite从点集合创建多边形

Question

从点列表创建多边形的最佳方法是什么？

我有一个点数组，如果点至少是3个，我想加入创建一个多边形。

Dim ClickedPoint As New NetTopologySuite.Geometries.Point(coordinates)
ClickedPointArray.Add(ClickedPoint)

if   ClickedPointArray.Count > 2 then

   Polygonizer = New Polygonizer()
   Polygonizer.Add(ClickedPointArray)

end if        

return Polygonizer.GetPolygons

我觉得我离解决方案还很远。你能帮我一下吗？

Answer 1

您可以使用GeometryFactory创建具有坐标数组的多边形，如下所示：

Dim coordinatesArray as Coordinate[] = YourMethodToGetCoordinates
Dim geomFactory As New GeometryFactory
Dim poly As geomFactory.CreatePolygon(coordinatesArray) //this returns an IPolygon that you can cast to Polygon

Answer 2

这是C#

Coordinate[] imageOutlineCoordinates = new Coordinate[] { new Coordinate(1, 1), new Coordinate(2, 1), new Coordinate(2, 2), new Coordinate(1, 1) }; GeometryFactory geometryFactory = new GeometryFactory(); Polygon poly = geometryFactory.CreatePolygon(imageOutlineCoordinates);

Answer 3

下面是使用网络拓扑套件(https://github.com/NetTopologySuite/NetTopologySuite)实现https://github.com/NetTopologySuite/NetTopologySuite的解决方案

Polygon GetGeometry(Coordinate[] coordinates)
        {
            var geometryFactory = new GeometryFactory(new PrecisionModel(), 4326);
            var polygon = new Polygon(new LinearRing(coordinates), geometryFactory);
            return polygon;
        }

注:此处4326为无坐标系。没有这个几何运算，就不能给出正确的结果。

var coordinates = new List<Coordinate>();


 for (var index = 0; index < doubleList.Count; index = index + 2)
    {
      var coordinate = new Coordinate(doubleList[index], doubleList[index + 1]);
        coordinates.Add(coordinate);
    }   


   coordinates.Add(new Coordinate(points[0], points[1]));
    
   GetGeometry(coordinates.ToArray())