用多个线段分割多边形

Question

我正在尝试使用多条线将线性环拆分为多个线性环。预期的结果是线性环的集合(如附图所示)。预期的结果是在这里附上的图像。(https://i.stack.imgur.com/Kuzr8.jpg)我不明白如何调用递归函数。下面是我试过的代码。

如果是单线切割多边形，我可以这样做。但这里的问题是，我们有多条线绳将多边形切割成多个"碎片"。另外，我知道每次如果当前线切割并制作当前多边形的两个部分，那么当前多边形应该从最终结果中删除。这对我来说有点复杂。

Main Function:

static void Main(string[] args)
{
Coordinate c22 = new Coordinate(2889.0, 1277.0);
Coordinate c23 = new Coordinate(2894.0, 1288.0);
Coordinate c24 = new Coordinate(2901.0, 1284.0);
Coordinate c25 = new Coordinate(2909.0, 1289.0);
Coordinate c26 = new Coordinate(2916.0, 1281.0);
Coordinate c27 = new Coordinate(2912.0, 1270.0);
Coordinate c28 = new Coordinate(2906.0, 1275.0);
Coordinate c29 = new Coordinate(2898.0, 1273.0);
LinearRing outerBoundary = new LinearRing(new Coordinate[] { c22, c23, c24, c25, c26, c27, c28, c29, c22 });
List<LineString> lines = new List<LineString>();
Coordinate p30 = new Coordinate(2892.0, 1270.0);
Coordinate p31 = new Coordinate(2900.0, 1294.0);
LineString ln1 = new LineString(new Coordinate[] { p30, p31 });
lines.Add(ln1);
Coordinate p32 = new Coordinate(2909.0, 1268.0);
Coordinate p33 = new Coordinate(2907.0, 1294.0);
LineString ln2 = new LineString(new Coordinate[] {p32, p33});
lines.Add(ln2);
Coordinate p34 = new Coordinate(2886.0, 1286.0);
Coordinate p35 = new Coordinate(2922.0, 1278.0);
LineString ln3 = new LineString(new Coordinate[] {p34, p35});
lines.Add(ln3);
Coordinate p36 = new Coordinate(2883.0, 1281.0);
Coordinate p37 = new Coordinate(2923.0, 1273.0);
LineString ln4 = new LineString(new Coordinate[] {p36, p37});
lines.Add(ln4);
Geometry polygons = CookieCutter(outerBoundary, new List<LineString>() { ln1, ln2, ln3, ln4 });
}

递归函数。这就是我被卡住的地方;

public static Geometry CookieCutter(LinearRing polygon, List<LineString> cuttingEdges, Geometry pieces = null)
{
if (pieces == null) { pieces = Polygonize(polygon.Union(cuttingEdges[0])); }
foreach (var cuttingEdge in cuttingEdges)
{
for (int i = 0; i < pieces.NumGeometries; i++)
{
pieces = pieces.GetGeometryN(i);
Geometry newPieces = Polygonize(polygon.Union(cuttingEdge));
// I know somewhere here it should call CookieCutter on new pieces
// But how to...?
}
}
}

这是多边形函数;

public static Geometry Polygonize(Geometry geometry)
{
var lines = LineStringExtracter.GetLines(geometry);
var polygonizer = new Polygonizer(false);
polygonizer.Add(lines);
var polys = new List<Geometry>(polygonizer.GetPolygons());
var polyArray = GeometryFactory.ToGeometryArray(polys);
return geometry.Factory.BuildGeometry(polyArray);
}

Answer 1

哦…解决办法很简单。我是在不必要地把事情复杂化。不需要任何递归。我是这样解决的;

public static Geometry CookieCutter(
Geometry polygon, 
List<LineString> cuttingEdges
)
{
MultiLineString mls = new MultiLineString(cuttingEdges.ToArray());
var union = polygon.Union(mls);
var polygons = Polygonize(union);
return polygons;
}