geometrytowkt.cs

Sharp Map 用于制作GIS系统S harp Map 用于制作GIS系统S harp Map 用于制作GIS系统

// Copyright 2005, 2006 - Morten Nielsen (www.iter.dk)
//
// This file is part of SharpMap.
// SharpMap is free software; you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
// 
// SharpMap is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Lesser General Public License for more details.

// You should have received a copy of the GNU Lesser General Public License
// along with SharpMap; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 

// SOURCECODE IS MODIFIED FROM ANOTHER WORK AND IS ORIGINALLY BASED ON GeoTools.NET:
/*
 *  Copyright (C) 2002 Urban Science Applications, Inc. 
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

using System;
using System.IO;
using System.Text;
using SharpMap.Geometries;

namespace SharpMap.Converters.WellKnownText
{
	/// <summary>
	/// Outputs the textual representation of a <see cref="SharpMap.Geometries.Geometry"/> instance.
	/// </summary>
	/// <remarks>
	/// <para>The Well-Known Text (WKT) representation of Geometry is designed to exchange geometry data in ASCII form.</para>
	/// Examples of WKT representations of geometry objects are:
	/// <list type="table">
	/// <listheader><term>Geometry </term><description>WKT Representation</description></listheader>
	/// <item><term>A Point</term>
	/// <description>POINT(15 20)<br/> Note that point coordinates are specified with no separating comma.</description></item>
	/// <item><term>A LineString with four points:</term>
	/// <description>LINESTRING(0 0, 10 10, 20 25, 50 60)</description></item>
	/// <item><term>A Polygon with one exterior ring and one interior ring:</term>
	/// <description>POLYGON((0 0,10 0,10 10,0 10,0 0),(5 5,7 5,7 7,5 7, 5 5))</description></item>
	/// <item><term>A MultiPoint with three Point values:</term>
	/// <description>MULTIPOINT(0 0, 20 20, 60 60)</description></item>
	/// <item><term>A MultiLineString with two LineString values:</term>
	/// <description>MULTILINESTRING((10 10, 20 20), (15 15, 30 15))</description></item>
	/// <item><term>A MultiPolygon with two Polygon values:</term>
	/// <description>MULTIPOLYGON(((0 0,10 0,10 10,0 10,0 0)),((5 5,7 5,7 7,5 7, 5 5)))</description></item>
	/// <item><term>A GeometryCollection consisting of two Point values and one LineString:</term>
	/// <description>GEOMETRYCOLLECTION(POINT(10 10), POINT(30 30), LINESTRING(15 15, 20 20))</description></item>
	/// </list>
	/// </remarks>
	public class GeometryToWKT
	{
		#region Methods

		/// <summary>
		/// Converts a Geometry to its Well-known Text representation.
		/// </summary>
		/// <param name="geometry">A Geometry to write.</param>
		/// <returns>A &lt;Geometry Tagged Text&gt; string (see the OpenGIS Simple
		///  Features Specification)</returns>
		public static string Write(IGeometry geometry)
		{
			StringWriter sw = new StringWriter();
			Write(geometry, sw);
			return sw.ToString();
		}

		/// <summary>
		/// Converts a Geometry to its Well-known Text representation.
		/// </summary>
		/// <param name="geometry">A geometry to process.</param>
		/// <param name="writer">Stream to write out the geometry's text representation.</param>
		/// <remarks>
		/// Geometry is written to the output stream as &lt;Gemoetry Tagged Text&gt; string (see the OpenGIS
		/// Simple Features Specification).
		/// </remarks>
		public static void Write(IGeometry geometry, StringWriter writer)
		{
			AppendGeometryTaggedText(geometry, writer);
		}

		/// <summary>
		/// Converts a Geometry to &lt;Geometry Tagged Text &gt; format, then Appends it to the writer.
		/// </summary>
		/// <param name="geometry">The Geometry to process.</param>
		/// <param name="writer">The output stream to Append to.</param>
		private static void AppendGeometryTaggedText(IGeometry geometry, StringWriter writer)
		{
			if (geometry == null)
				throw new NullReferenceException("Cannot write Well-Known Text: geometry was null"); ;
			if (geometry is Point) 
			{
				Point point = geometry as Point;
				AppendPointTaggedText(point, writer);
			}
			else if (geometry is LineString) 
				AppendLineStringTaggedText(geometry as LineString, writer);
			else if (geometry is Polygon) 
				AppendPolygonTaggedText(geometry as Polygon, writer);
			else if (geometry is MultiPoint) 
				AppendMultiPointTaggedText(geometry as MultiPoint, writer);
			else if (geometry is MultiLineString) 
				AppendMultiLineStringTaggedText(geometry as MultiLineString, writer);
			else if (geometry is MultiPolygon) 
				AppendMultiPolygonTaggedText(geometry as MultiPolygon, writer);
			else if (geometry is GeometryCollection) 
				AppendGeometryCollectionTaggedText(geometry as GeometryCollection, writer);
			else 
				throw new NotSupportedException("Unsupported Geometry implementation:"+ geometry.GetType().Name);
		}

		/// <summary>
		/// Converts a Coordinate to &lt;Point Tagged Text&gt; format,
		/// then Appends it to the writer.
		/// </summary>
		/// <param name="coordinate">the <code>Coordinate</code> to process</param>
		/// <param name="writer">the output writer to Append to</param>
		private static void AppendPointTaggedText(Point coordinate, StringWriter writer)
		{
			writer.Write("POINT ");
			AppendPointText(coordinate, writer);
		}

		/// <summary>
		/// Converts a LineString to LineString tagged text format, 
		/// </summary>
		/// <param name="lineString">The LineString to process.</param>
		/// <param name="writer">The output stream writer to Append to.</param>
		private static void AppendLineStringTaggedText(LineString lineString, StringWriter writer)
		{
			writer.Write("LINESTRING ");
			AppendLineStringText(lineString, writer);
		}

		/// <summary>
		///  Converts a Polygon to &lt;Polygon Tagged Text&gt; format,
		///  then Appends it to the writer.
		/// </summary>
		/// <param name="polygon">Th Polygon to process.</param>
		/// <param name="writer">The stream writer to Append to.</param>
		private static void AppendPolygonTaggedText(Polygon polygon, StringWriter writer)
		{
			writer.Write("POLYGON ");
			AppendPolygonText(polygon, writer);
		}

		/// <summary>
		/// Converts a MultiPoint to &lt;MultiPoint Tagged Text&gt;
		/// format, then Appends it to the writer.
		/// </summary>
		/// <param name="multipoint">The MultiPoint to process.</param>
		/// <param name="writer">The output writer to Append to.</param>
		private static void AppendMultiPointTaggedText(MultiPoint multipoint, StringWriter writer)
		{
			writer.Write("MULTIPOINT ");
			AppendMultiPointText(multipoint, writer);
		}

		/// <summary>
		/// Converts a MultiLineString to &lt;MultiLineString Tagged
		/// Text&gt; format, then Appends it to the writer.
		/// </summary>
		/// <param name="multiLineString">The MultiLineString to process</param>
		/// <param name="writer">The output stream writer to Append to.</param>
		private static void AppendMultiLineStringTaggedText(MultiLineString multiLineString, StringWriter writer)
		{
			writer.Write("MULTILINESTRING ");
			AppendMultiLineStringText(multiLineString, writer);
		}

		/// <summary>
		/// Converts a MultiPolygon to &lt;MultiPolygon Tagged
		/// Text&gt; format, then Appends it to the writer.
		/// </summary>
		/// <param name="multiPolygon">The MultiPolygon to process</param>
		/// <param name="writer">The output stream writer to Append to.</param>
		private static void AppendMultiPolygonTaggedText(MultiPolygon multiPolygon, StringWriter writer)
		{
			
			writer.Write("MULTIPOLYGON ");
			AppendMultiPolygonText(multiPolygon, writer);
			
		}

		/// <summary>
		/// Converts a GeometryCollection to &lt;GeometryCollection Tagged
		/// Text&gt; format, then Appends it to the writer.
		/// </summary>
		/// <param name="geometryCollection">The GeometryCollection to process</param>
		/// <param name="writer">The output stream writer to Append to.</param>
		private static void AppendGeometryCollectionTaggedText(GeometryCollection geometryCollection, StringWriter writer)
		{
			writer.Write("GEOMETRYCOLLECTION ");
			AppendGeometryCollectionText(geometryCollection, writer);
		}


		/// <summary>
		/// Converts a Coordinate to Point Text format then Appends it to the writer.
		/// </summary>
		/// <param name="coordinate">The Coordinate to process.</param>
		/// <param name="writer">The output stream writer to Append to.</param>
		private static void AppendPointText(Point coordinate, StringWriter writer)
		{
			if (coordinate == null || coordinate.IsEmpty()) 
				writer.Write("EMPTY");
			else 
			{
				writer.Write("(");
				AppendCoordinate(coordinate, writer);
				writer.Write(")");
			}
		}

		/// <summary>
		/// Converts a Coordinate to &lt;Point&gt; format, then Appends
		/// it to the writer. 
		/// </summary>
		/// <param name="coordinate">The Coordinate to process.</param>
		/// <param name="writer">The output writer to Append to.</param>
		private static void AppendCoordinate(Point coordinate, StringWriter writer)
		{
			for(uint i=0;i<coordinate.NumOrdinates;i++)
				writer.Write(WriteNumber(coordinate[i]) + (i<coordinate.NumOrdinates-1?" ":""));
		}

		/// <summary>
		/// Converts a double to a string, not in scientific notation.
		/// </summary>
		/// <param name="d">The double to convert.</param>
		/// <returns>The double as a string, not in scientific notation.</returns>
		private static string WriteNumber(double d) 
		{
			return d.ToString(SharpMap.Map.numberFormat_EnUS);
		}

		/// <summary>
		/// Converts a LineString to &lt;LineString Text&gt; format, then
		/// Appends it to the writer.
		/// </summary>
		/// <param name="lineString">The LineString to process.</param>
		/// <param name="writer">The output stream to Append to.</param>
		private static void AppendLineStringText(LineString lineString, StringWriter writer)
		{
			
			if (lineString==null || lineString.IsEmpty() ) 
				writer.Write("EMPTY");
			else 
			{
				writer.Write("(");
				for (int i = 0; i < lineString.NumPoints; i++) 
				{
					if (i > 0) 
						writer.Write(", ");
					AppendCoordinate( lineString.Vertices[i], writer);
				}
				writer.Write(")");
			}
		}

		/// <summary>
		/// Converts a Polygon to &lt;Polygon Text&gt; format, then
		/// Appends it to the writer.
		/// </summary>
		/// <param name="polygon">The Polygon to process.</param>
		/// <param name="writer"></param>
		private static void AppendPolygonText(Polygon polygon, StringWriter writer)
		{
			if (polygon == null || polygon.IsEmpty() ) 
				writer.Write("EMPTY");
			else 
			{
				writer.Write("(");
				AppendLineStringText(polygon.ExteriorRing, writer);
				for (int i = 0; i < polygon.InteriorRings.Count; i++) 
				{
					writer.Write(", ");
					AppendLineStringText(polygon.InteriorRings[i], writer);
				}
				writer.Write(")");
			}		
		}

		/// <summary>
		/// Converts a MultiPoint to &lt;MultiPoint Text&gt; format, then
		/// Appends it to the writer.
		/// </summary>
		/// <param name="multiPoint">The MultiPoint to process.</param>
		/// <param name="writer">The output stream writer to Append to.</param>
		private static void AppendMultiPointText(MultiPoint multiPoint, StringWriter writer)
		{
			
			if(multiPoint == null || multiPoint.IsEmpty() ) 
				writer.Write("EMPTY");
			else 
			{
				writer.Write("(");
				for (int i = 0; i < multiPoint.Points.Count; i++) 
				{
					if (i > 0) 
						writer.Write(", ");
					AppendCoordinate(multiPoint[i], writer);
				}
				writer.Write(")");
			}
		}

		/// <summary>
		/// Converts a MultiLineString to &lt;MultiLineString Text&gt;
		/// format, then Appends it to the writer.
		/// </summary>
		/// <param name="multiLineString">The MultiLineString to process.</param>
		/// <param name="writer">The output stream writer to Append to.</param>
		private static void AppendMultiLineStringText(MultiLineString multiLineString, StringWriter writer)
		{
			
			if (multiLineString == null || multiLineString.IsEmpty() ) 
				writer.Write("EMPTY");
			else 
			{
				writer.Write("(");
				for (int i = 0; i < multiLineString.LineStrings.Count; i++) 
				{
					if (i > 0) 
						writer.Write(", ");
					AppendLineStringText(multiLineString[i], writer);
				}
				writer.Write(")");
			}
		}

		/// <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(MultiPolygon multiPolygon, StringWriter writer)
		{
			
			if (multiPolygon==null || multiPolygon.IsEmpty() ) 
				writer.Write("EMPTY");
			else 
			{
				writer.Write("(");
				for (int i = 0; i < multiPolygon.Polygons.Count; i++) 
				{
					if (i > 0) 
						writer.Write(", ");
					AppendPolygonText(multiPolygon[i], writer);
				}
				writer.Write(")");
			}
		}

		/// <summary>
		/// Converts a GeometryCollection to &lt;GeometryCollection Text &gt; format, then Appends it to the writer.
		/// </summary>
		/// <param name="geometryCollection">The GeometryCollection to process.</param>
		/// <param name="writer">The output stream writer to Append to.</param>
		private static void AppendGeometryCollectionText(GeometryCollection geometryCollection, StringWriter writer)
		{			
			if (geometryCollection==null || geometryCollection.IsEmpty() ) 
				writer.Write("EMPTY");
			else 
			{
				writer.Write("(");
				for (int i = 0; i < geometryCollection.Collection.Count; i++) 
				{
					if (i > 0) 
						writer.Write(", ");
					AppendGeometryTaggedText(geometryCollection[i], writer);
				}
				writer.Write(")");
			}
		}
		#endregion
	}
}