Polylgon对象是由一个或多个Ring对象的有序集合，它可以是由单个Ring对象构成，也可以使用多个Ring组成。其中Ring可以分为Outer Ring(外环)和InnerRing(内环)之分。外环和内环都是有方向的，它们的区别是外环的方向是顺时针的，内环的方向是逆时针。如果多边形只有外环，没有内环，很好处理，难得是如何将内环和外环区分开来，并且保证正确的内外环包含关系。前段时间做MDB数据库的坐标转换功能，由于针对的是地方坐标系，所以无法用7参数构建投影坐标统一转换。我采用的是将featureLayer中的Feature一个一个取出来，将每个点的起始点坐标取出来进行转换，然后再组合回去。现在将多边形部分代码贴出来： IPolygon4 polygon = pFeature.ShapeCopy as IPolygon4; IGeometryBag bag = polygon.ExteriorRingBag; //获取多边形的所有外环 IEnumGeometry geo = bag as IEnumGeometry; geo.Reset(); IRing exRing = geo.Next() as IRing; while (exRing != null) { IGeometryBag bags = polygon.get_InteriorRingBag(exRing); //获取当前外环所包含的内环 IEnumGeometry geos = bags as IEnumGeometry; geos.Reset(); IRing inRing = geos.Next() as IRing; while (inRing != null) //先处理内环 { ISegmentCollection segs = inRing as ISegmentCollection; ISegmentCollection ring = new RingClass(); //创建新的ring对象，以重新组合polygon for (int i = 0; i < segs.SegmentCount; i++) { object o = Type.Missing; ISegment s = segs.get_Segment(i); IPoint fromPoint = s.FromPoint; IPoint toPoint = s.ToPoint; x = fromPoint.X; y = fromPoint.Y; fromPoint.PutCoords(ConvertTo2000X(x, y), ConvertTo2000Y(x, y)); //将X、Y坐标转换 s.FromPoint = fromPoint; x1 = toPoint.X; y1 = toPoint.Y; toPoint.PutCoords(ConvertTo2000X(x1, y1), ConvertTo2000Y(x1, y1)); s.ToPoint = toPoint; ring.AddSegment(s, ref o, ref o); } IRing ir = ring as IRing; ir.Close(); ppolygon.AddGeometry(ir); inRing = geos.Next() as IRing; } ISegmentCollection seg = exRing as ISegmentCollection; ISegmentCollection rings = new RingClass(); for (int i = 0; i < seg.SegmentCount; i++) //处理外环 { object o = Type.Missing; ISegment s = seg.get_Segment(i); IPoint fromPoint = s.FromPoint; IPoint toPoint = s.ToPoint; x = fromPoint.X; y = fromPoint.Y; fromPoint.PutCoords(ConvertTo2000X(x, y), ConvertTo2000Y(x, y)); s.FromPoint = fromPoint; x1 = toPoint.X; y1 = toPoint.Y; toPoint.PutCoords(ConvertTo2000X(x1, y1), ConvertTo2000Y(x1, y1)); s.ToPoint = toPoint; rings.AddSegment(s, ref o, ref o); } IRing irr = rings as IRing; irr.Close(); ppolygon.AddGeometry(irr); exRing = geo.Next() as IRing; } IPolygon p = ppolygon as IPolygon; p.SimplifyPreserveFromTo(); //保证多边形封闭 pFeature.Shape = p; pFeature.Store(); 通过以上的方法能够将polygon取出来，实现自定义的坐标转换过程，由于先取出来然后再重新组合，所以效率不是很高，但是经过大数据量的验证，表明效率能够接受。

ArcEngine中多边形内外环的处理

vip888

Polylgon对象是由一个或多个Ring对象的有序集合，它可以是由单个Ring对象构成，也可以使用多个Ring组成。其中Ring可以分为Outer Ring(外环)和InnerRing(内环)之分。外环和内环都是有方向的，它们的区别是外环的方向是顺时针的，内环的方向是逆时针。如果多边形只有外环，没有内环，很好处理，难得是如何将内环和外环区分开来，并且保证正确的内外环包含关系。
前段时间做MDB数据库的坐标转换功能，由于针对的是地方坐标系，所以无法用7参数构建投影坐标统一转换。我采用的是将featureLayer中的Feature一个一个取出来，将每个点的起始点坐标取出来进行转换，然后再组合回去。现在将多边形部分代码贴出来：

 IPolygon4 polygon = pFeature.ShapeCopy as IPolygon4;
IGeometryBag bag = polygon.ExteriorRingBag;     //获取多边形的所有外环
IEnumGeometry geo = bag as IEnumGeometry;
geo.Reset();
IRing exRing = geo.Next() as IRing;
while (exRing != null)
{
    IGeometryBag bags = polygon.get_InteriorRingBag(exRing);   //获取当前外环所包含的内环
    IEnumGeometry geos = bags as IEnumGeometry;
    geos.Reset();
    IRing inRing = geos.Next() as IRing;
    while (inRing != null)   //先处理内环
    {
        ISegmentCollection segs = inRing as ISegmentCollection;
        ISegmentCollection ring = new Rin

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