arcobjects,arcengine处理自相交对象

内容摘要

很多线划图数据进ArcSDE库中都会有些对象转换不进去。这些对象有很大一部分是由于数据本身有自相交的情况。如果这些线划图数据只是用来做底图，而不需要做对象分析。则可以采用数据简单化操作后再转换入ArcSDE中。具体操作如下例子：

delphi

//简单拓扑一个对象

procedure IsSimple(var PGeoMetry: IGeoMetry);
var
    pTopo                               : ITopologicalOperator;
    PGeoMetryCollect                    : IGeoMetryCollection;
    ShapeType                           : TOleEnum;
    OldGeoMetry                         : IGeoMetry;

begin
    if IsEmpty(PGeoMetry) then Exit;
    OldGeoMetry := CopyGeoMetry(PGeoMetry);  //拷贝一个原始的对象，因为 有些IsSimple后，原来不为空，处理后为空
    PGeoMetry.Get_GeometryType(ShapeType);
    if ShapeType = esriGeometryPoint then Exit;
    if ShapeType = esriGeometryRing then
    begin
        PGeoMetry := CreatePolygonfromRing(PGeoMetry as IRing);

    end;

    PGeoMetryCollect := PGeoMetry as IGeoMetryCollection;
    try
        PGeoMetryCollect.GeometriesChanged;

        pTopo := PGeoMetry as ITopologicalOperator;

        pTopo.Simplify;
        if IsEmpty(PGeoMetry) then
        begin
            PGeoMetry := OldGeoMetry;
        end;
    except
    end;

end; 

C#

/处理自相交对象

        public static bool IsSimple(ref IGeometry PGeoMetry)

        {

            if (PGeoMetry == null)

            {

                return false;//不用处理

            }

            if (PGeoMetry.GeometryType == esriGeometryType.esriGeometryPoint) //不做任何处理

            {

                return false;//不用处理

            }

            IGeometry oldGeoMetry = CopyGeoMetry(PGeoMetry); //拷贝一个原始的对象，因为有些IsSimple后，原来不为空，处理后为空

            if (PGeoMetry.GeometryType == esriGeometryType.esriGeometryRing) //不做任何处理

            {

                PGeoMetry = CreatePolygonfromRing((IRing)(PGeoMetry));

 

            }

            IGeometryCollection PGeoMetryCollect = PGeoMetry as IGeometryCollection;

            PGeoMetryCollect.GeometriesChanged();

            ITopologicalOperator pTopo = PGeoMetry as ITopologicalOperator;

 

            pTopo.Simplify();

            if (IsEmpty(PGeoMetry))

            {

                PGeoMetry = oldGeoMetry;

                return false;

            }

            else

 

                return true;//对象修改

 

        }

 //C#例子

IGeometry SimplifyGeometry(IGeometry geom)

{

    if (geom == null)

    return null;

 

    ITopologicalOperator2 topoOp = geom as ITopologicalOperator2;

    topoOp.IsKnownSimple_2 = false;

 

    switch (geom.GeometryType)

    {

        case esriGeometryType.esriGeometryPolygon:

        {

            IPolygon poly = (IPolygon)geom;

            poly.SimplifyPreserveFromTo();

            return poly;

        }

        case esriGeometryType.esriGeometryPolyline:

        {

            IPolyline polyLineGeom = (IPolyline)geom;

            polyLineGeom.SimplifyNetwork();

            return polyLineGeom;

        }

        default:

        {

            topoOp.Simplify();

            return (IGeometry)topoOp;

        }

    }

}