Beispiel #1
0
        /// <summary>
        /// Writes a shapefile to disk.
        /// </summary>
        /// <remarks>
        /// Assumes the type given for the first geometry is the same for all subsequent geometries.
        /// For example, is, if the first Geometry is a Multi-polygon/ Polygon, the subsequent geometies are
        /// Muli-polygon/ polygon and not lines or points.
        /// The dbase file for the corresponding shapefile contains one column called row. It contains
        /// the row number.
        /// </remarks>
        /// <param name="filename">The filename to write to (minus the .shp extension).</param>
        /// <param name="geometryCollection">The GeometryCollection to write.</param>
        public void Write(IGeometryCollection geometryCollection)
        {
            //FileStream shpStream = new FileStream(filename + ".shp", FileMode.Create);
            //FileStream shxStream = new FileStream(filename + ".shx", FileMode.Create);

            shpStream = new MemoryStream();
            shxStream = new MemoryStream();
            BigEndianBinaryWriter shpBinaryWriter = new BigEndianBinaryWriter(shpStream);
            BigEndianBinaryWriter shxBinaryWriter = new BigEndianBinaryWriter(shxStream);

            // assumes
            ShapeHandler handler = Shapefile.GetShapeHandler(Shapefile.GetShapeType(geometryCollection.Geometries[0]));

            IGeometry body;
            int       numShapes = geometryCollection.NumGeometries;
            // calc the length of the shp file, so it can put in the header.
            int shpLength = 50;

            for (int i = 0; i < numShapes; i++)
            {
                body       = (IGeometry)geometryCollection.Geometries[i];
                shpLength += 4;                       // length of header in WORDS
                shpLength += handler.GetLength(body); // length of shape in WORDS
            }

            int shxLength = 50 + (4 * numShapes);

            // write the .shp header
            ShapefileHeader shpHeader = new ShapefileHeader();

            shpHeader.FileLength = shpLength;

            // get envelope in external coordinates
            Envelope env    = geometryCollection.EnvelopeInternal as Envelope;
            Envelope bounds = ShapeHandler.GetEnvelopeExternal(geometryFactory.PrecisionModel, env);

            shpHeader.Bounds = bounds;

            // assumes Geometry type of the first item will the same for all other items
            // in the collection.
            shpHeader.ShapeType = Shapefile.GetShapeType(geometryCollection.Geometries[0]);
            shpHeader.Write(shpBinaryWriter);

            // write the .shx header
            ShapefileHeader shxHeader = new ShapefileHeader();

            shxHeader.FileLength = shxLength;
            shxHeader.Bounds     = shpHeader.Bounds;

            // assumes Geometry type of the first item will the same for all other items in the collection.
            shxHeader.ShapeType = Shapefile.GetShapeType(geometryCollection.Geometries[0]);
            shxHeader.Write(shxBinaryWriter);

            // write the individual records.
            int _pos = 50; // header length in WORDS

            for (int i = 0; i < numShapes; i++)
            {
                body = geometryCollection.Geometries[i];
                int recordLength = handler.GetLength(body);
                shpBinaryWriter.WriteIntBE(i + 1);
                shpBinaryWriter.WriteIntBE(recordLength);

                shxBinaryWriter.WriteIntBE(_pos);
                shxBinaryWriter.WriteIntBE(recordLength);

                _pos += 4;            // length of header in WORDS
                handler.Write(body, shpBinaryWriter, geometryFactory);
                _pos += recordLength; // length of shape in WORDS
            }

            shxBinaryWriter.Flush();
            //shxStream.Seek(0, SeekOrigin.Begin);
            ////shxBinaryWriter.Close();
            shpBinaryWriter.Flush();
            //shpStream.Seek(0, SeekOrigin.Begin);
            //shpBinaryWriter.Close();

            // WriteDummyDbf(filename + ".dbf", numShapes);
        }