C# IMultiPolygon.GetGeometryN方法代码示例

        /// <summary>
        /// Transforms a <see cref="GeoAPI.Geometries.IMultiPolygon"/>.
        /// </summary>
        /// <param name="polys">MultiPolygon to transform</param>
        /// <param name="from">Source Projection</param>
        /// <param name="to">Target Projection</param>
        /// <param name="toFactory">The factory to create geometries for <paramref name="to"/></param>
        /// <returns>Transformed MultiPolygon</returns>
        public static IMultiPolygon TransformMultiPolygon(IMultiPolygon polys, ProjectionInfo from, ProjectionInfo to, IGeometryFactory toFactory)
        {
            var pOut = new IPolygon[polys.Count];
            for (var i = 0; i < polys.Count; i++)
                pOut[i] = TransformPolygon((IPolygon)polys.GetGeometryN(i), from, to, toFactory);

            return toFactory.CreateMultiPolygon(pOut);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="multiPolygon"></param>
        /// <param name="writer"></param>
        public void Write(IMultiPolygon multiPolygon, BinaryWriter writer)
        {
            writer.Write((int) ShapeGeometryTypes.Polygon);

            // Write BoundingBox            
            WriteBoundingBox(multiPolygon, writer);

            // Write NumParts and NumPoints
            int numParts = multiPolygon.NumGeometries;              // Exterior rings count
            for (int i = 0; i < multiPolygon.NumGeometries; i++)    // Adding interior rings count            
                numParts += ((IPolygon) multiPolygon.GetGeometryN(i)).NumInteriorRings;

            writer.Write((int) numParts);
            writer.Write((int) multiPolygon.NumPoints);

            // Write IndexParts
            int count = 0;
            writer.Write((int) count);

            for (int i = 0; i < multiPolygon.NumGeometries; i++)
            {
                IPolygon polygon = (IPolygon) multiPolygon.GetGeometryN(i);
                ILineString shell = polygon.ExteriorRing;
                count += shell.NumPoints;
                if (count == multiPolygon.NumPoints)
                    break;
                writer.Write((int) count);
                for (int j = 0; j < polygon.NumInteriorRings; j++)
                {
                    ILineString hole = (ILineString) polygon.GetInteriorRingN(j);
                    count += hole.NumPoints;
                    if (count == multiPolygon.NumPoints)
                        break;
                    writer.Write((int) count);
                }
            }

            // Write Coordinates
            for (int i = 0; i < multiPolygon.NumPoints; i++)
                Write(multiPolygon.Coordinates[i], writer);
        }

 /// <summary>
 /// Converts a <c>MultiPolygon</c> to &lt;MultiPolygon Text format,
 /// then appends it to the writer.
 /// </summary>
 /// <param name="multiPolygon">The <c>MultiPolygon</c> to process.</param>
 /// <param name="level"></param>
 /// <param name="writer">The output writer to append to.</param>
 private void AppendMultiPolygonText(IMultiPolygon multiPolygon, int level, TextWriter writer)            
 {
     if (multiPolygon.IsEmpty) 
         writer.Write(" EMPTY");            
     else 
     {
         int level2 = level;
         bool doIndent = false;
         writer.Write("(");
         for (int i = 0; i < multiPolygon.NumGeometries; i++) 
         {
             if (i > 0) 
             {
                 writer.Write(",");
                 level2 = level + 1;
                 doIndent = true;
             }
             AppendPolygonText((IPolygon) multiPolygon.GetGeometryN(i), level2, doIndent, writer);
         }
         writer.Write(")");
     }
 }

        /// <summary>
        /// Writes a multipolygon.
        /// </summary>
        /// <param name="mp">The mulitpolygon to be written.</param>
        /// <param name="bWriter">Stream to write to.</param>
        /// <param name="byteorder">Byte order</param>
        private static void WriteMultiPolygon(IMultiPolygon mp, BinaryWriter bWriter, WkbByteOrder byteorder)
        {
            //Write the number of polygons.
            int num = mp.NumGeometries;
            WriteUInt32((uint) num, bWriter, byteorder);

            //Loop on the number of polygons.
            //NOTE: by contract, the first item returned 
            //      from GetEnumerator (i.e. using foreach) is the IMultiPolygon itself!
            for (int i = 0; i < num; i++)
            {
                IPolygon poly = (IPolygon) mp.GetGeometryN(i);
                //Write polygon header
                bWriter.Write((byte) byteorder);
                WriteUInt32((uint) WKBGeometryType.wkbPolygon, bWriter, byteorder);
                //Write each polygon.
                WritePolygon(poly, bWriter, byteorder);
            }
        }

 /// <summary>
 /// 
 /// </summary>
 /// <param name="geom"></param>
 /// <param name="parent"></param>
 /// <returns></returns>
 protected virtual IGeometry TransformMultiPolygon(IMultiPolygon geom, IGeometry parent) 
 {
     ArrayList transGeomList = new ArrayList();
     for (int i = 0; i < geom.NumGeometries; i++) 
     {
         IGeometry transformGeom = TransformPolygon((IPolygon) geom.GetGeometryN(i), geom);
         if (transformGeom == null) continue;
         if (transformGeom.IsEmpty) continue;
         transGeomList.Add(transformGeom);
     }
     return factory.BuildGeometry(transGeomList);
 }

        private static DSMultiPolygon FromMultiPolygon(IMultiPolygon geometry, DSGeometryFactory factory, bool setUserData)
        {
            var dsPolygons = new DotSpatial.Topology.IPolygon[geometry.NumGeometries];

            for (var i = 0; i < dsPolygons.Length; i++)
                dsPolygons[i] = FromPolygon((IPolygon)geometry.GetGeometryN(i), factory, setUserData);

            var result = factory.CreateMultiPolygon(dsPolygons);
            if (setUserData)
                result.UserData = geometry.UserData;
            return result;
        }

        private static GeoAPIMultiPolygon FromMultiPolygon(IMultiPolygon geometry, GeoAPIGeometryFactory factory, bool copyUserData)
        {
            var dsPolygons = new GeoAPI.Geometries.IPolygon[geometry.NumGeometries];

            for (var i = 0; i < dsPolygons.Length; i++)
                dsPolygons[i] = FromPolygon((IPolygon)geometry.GetGeometryN(i), factory, copyUserData);

            var result = factory.CreateMultiPolygon(dsPolygons);
            if (copyUserData)
                result.UserData = geometry.UserData;
            return result;
        }

 /// <summary>
 /// Tests that no element polygon is wholly in the interior of another element polygon.
 /// Preconditions:
 /// Shells do not partially overlap.
 /// Shells do not touch along an edge.
 /// No duplicate rings exists.
 /// This routine relies on the fact that while polygon shells may touch at one or
 /// more vertices, they cannot touch at ALL vertices.
 /// </summary>
 private void CheckShellsNotNested(IMultiPolygon mp, GeometryGraph graph)
 {            
     for (int i = 0; i < mp.NumGeometries; i++)
     {                
         IPolygon p = (IPolygon) mp.GetGeometryN(i);
         ILinearRing shell = p.Shell;
         for (int j = 0; j < mp.NumGeometries; j++)
         {                    
             if (i == j)
                 continue;
             IPolygon p2 = (IPolygon) mp.GetGeometryN(j);                    
             CheckShellNotNested(shell, p2, graph);
             if (validErr != null) return;
         }                
     }         
 }

 /// <summary>
 /// Converts a MultiPolygon to &lt;MultiPolygon Text&gt; format, then Appends to it to the writer.
 /// </summary>
 /// <param name="multiPolygon">The MultiPolygon to process.</param>
 /// <param name="writer">The output stream to Append to.</param>
 private static void AppendMultiPolygonText(IMultiPolygon multiPolygon, StringWriter writer)
 {
     if (multiPolygon == null || multiPolygon.IsEmpty)
         writer.Write("EMPTY");
     else
     {
         writer.Write("(");
         for (int i = 0; i < multiPolygon.NumGeometries; i++)
         {
             if (i > 0)
                 writer.Write(", ");
             AppendPolygonText((IPolygon)multiPolygon.GetGeometryN(i), writer);
         }
         writer.Write(")");
     }
 }