geometryprovider.cs

C# 的地图开发例子（sharp map)

// Copyright 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 

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
using SharpMap.Geometries;
using SharpMap.Data;

namespace SharpMap.Data.Providers
{
	/// <summary>
	/// Datasource for storing a limited set of geometries.
	/// </summary>
	/// <remarks>
	/// <para>The GeometryProvider doesn抰 utilize performance optimizations of spatial indexing,
	/// and thus is primarily meant for rendering a limited set of Geometries.</para>
	/// <para>A common use of the GeometryProvider is for highlighting a set of selected features.</para>
	/// <example>
	/// The following example gets data within a BoundingBox of another datasource and adds it to the map.
	/// <code lang="C#">
	/// List&#60;Geometry&#62; geometries = myMap.Layers[0].DataSource.GetGeometriesInView(myBox);
	/// VectorLayer laySelected = new VectorLayer("Selected Features");
	/// laySelected.DataSource = new GeometryProvider(geometries);
	/// laySelected.Style.Outline = new Pen(Color.Magenta, 3f);
	/// laySelected.Style.EnableOutline = true;
	/// myMap.Layers.Add(laySelected);
	/// </code>
	/// </example>
	/// <example>
	/// Adding points of interest to the map. This is useful for vehicle tracking etc.
	/// <code lang="C#">
	/// List&#60;SharpMap.Geometries.Geometry&#62; geometries = new List&#60;SharpMap.Geometries.Geometry&#62;();
	/// //Add two points
	/// geometries.Add(new SharpMap.Geometries.Point(23.345,64.325));
	/// geometries.Add(new SharpMap.Geometries.Point(23.879,64.194));
	/// SharpMap.Layers.VectorLayer layerVehicles = new SharpMap.Layers.VectorLayer("Vechicles");
	/// layerVehicles.DataSource = new SharpMap.Data.Providers.GeometryProvider(geometries);
	/// layerVehicles.Style.Symbol = Bitmap.FromFile(@"C:\data\car.gif");
	/// myMap.Layers.Add(layerVehicles);
	/// </code>
	/// </example>
	/// </remarks>
	public class GeometryProvider : SharpMap.Data.Providers.IProvider, IDisposable
	{
		private Collection<Geometry> _Geometries;

		/// <summary>
		/// Gets or sets the geometries this datasource contains
		/// </summary>
		public Collection<Geometry> Geometries
		{
			get { return _Geometries; }
			set { _Geometries = value; }
		}

		#region constructors

		/// <summary>
		/// Initializes a new instance of the <see cref="GeometryProvider"/>
		/// </summary>
		/// <param name="geometries">Set of geometries that this datasource should contain</param>
		public GeometryProvider(Collection<Geometry> geometries)
		{
			_Geometries = geometries;
		}

		/// <summary>
		/// Initializes a new instance of the <see cref="GeometryProvider"/>
		/// </summary>
		/// <param name="feature">Feature to be in this datasource</param>
		public GeometryProvider(FeatureDataRow feature)
		{
			_Geometries = new Collection<Geometry>();
			_Geometries.Add(feature.Geometry);
		}

		/// <summary>
		/// Initializes a new instance of the <see cref="GeometryProvider"/>
		/// </summary>
		/// <param name="features">Features to be included in this datasource</param>
		public GeometryProvider(FeatureDataTable features)
		{
			_Geometries = new Collection<Geometry>();
			for (int i = 0; i < features.Count;i++ )
				_Geometries.Add(features[i].Geometry);
		}

		/// <summary>
		/// Initializes a new instance of the <see cref="GeometryProvider"/>
		/// </summary>
		/// <param name="geometry">Geometry to be in this datasource</param>
		public GeometryProvider(Geometry geometry)
		{
			_Geometries = new Collection<Geometry>();
			_Geometries.Add(geometry);
		}

		/// <summary>
		/// Initializes a new instance of the <see cref="GeometryProvider"/>
		/// </summary>
		/// <param name="wellKnownBinaryGeometry"><see cref="SharpMap.Geometries.Geometry"/> as Well-known Binary to be included in this datasource</param>
		public GeometryProvider(byte[] wellKnownBinaryGeometry) : this(SharpMap.Converters.WellKnownBinary.GeometryFromWKB.Parse(wellKnownBinaryGeometry))
		{
		}

		/// <summary>
		/// Initializes a new instance of the <see cref="GeometryProvider"/>
		/// </summary>
		/// <param name="wellKnownTextGeometry"><see cref="SharpMap.Geometries.Geometry"/> as Well-known Text to be included in this datasource</param>
		public GeometryProvider(string wellKnownTextGeometry) : this(SharpMap.Converters.WellKnownText.GeometryFromWKT.Parse(wellKnownTextGeometry))
		{
		}

		#endregion

		#region IProvider Members

		/// <summary>
		/// Returns features within the specified bounding box
		/// </summary>
		/// <param name="bbox"></param>
		/// <returns></returns>
		public Collection<Geometry> GetGeometriesInView(BoundingBox bbox)
		{
			Collection<Geometry> list = new Collection<Geometry>();
			for (int i = 0; i < _Geometries.Count; i++)
				if(!_Geometries[i].IsEmpty())
				if (_Geometries[i].GetBoundingBox().Intersects(bbox))
					list.Add(_Geometries[i]);
			return list;
		}

		/// <summary>
		/// Returns all objects whose boundingbox intersects 'bbox'.
		/// </summary>
		/// <param name="bbox"></param>
		/// <returns></returns>
		public Collection<uint> GetObjectIDsInView(BoundingBox bbox)
		{
			Collection<uint> list = new Collection<uint>();
			for (int i = 0; i < _Geometries.Count; i++)
				if(_Geometries[i].GetBoundingBox().Intersects(bbox))
					list.Add((uint)i);
			return list;
		}

		/// <summary>
		/// Returns the geometry corresponding to the Object ID
		/// </summary>
		/// <param name="oid">Object ID</param>
		/// <returns>geometry</returns>
		public Geometry GetGeometryByID(uint oid)
		{
			return _Geometries[(int)oid];
		}
				
		/// <summary>
		/// Throws an NotSupportedException. Attribute data is not supported by this datasource
		/// </summary>
		/// <param name="geom"></param>
		/// <param name="ds">FeatureDataSet to fill data into</param>
		public void ExecuteIntersectionQuery(Geometry geom, FeatureDataSet ds)
		{
			throw new NotSupportedException("Attribute data is not supported by the GeometryProvider.");
		}
		/// <summary>
		/// Throws an NotSupportedException. Attribute data is not supported by this datasource
		/// </summary>
		/// <param name="box"></param>
		/// <param name="ds">FeatureDataSet to fill data into</param>
		public void ExecuteIntersectionQuery(SharpMap.Geometries.BoundingBox box, FeatureDataSet ds)
		{
			throw new NotSupportedException("Attribute data is not supported by the GeometryProvider.");
		}

		/// <summary>
		/// Returns the number of features in the dataset
		/// </summary>
		/// <returns>number of features</returns>
		public int GetFeatureCount()
		{
			return _Geometries.Count;
		}

		/// <summary>
		/// Throws an NotSupportedException. Attribute data is not supported by this datasource
		/// </summary>
		/// <param name="RowID"></param>
		/// <returns></returns>
		public FeatureDataRow GetFeature(uint RowID)
		{
			throw new NotSupportedException("Attribute data is not supported by the GeometryProvider.");
		}

		/// <summary>
		/// Boundingbox of dataset
		/// </summary>
		/// <returns>boundingbox</returns>
		public BoundingBox GetExtents()
		{
			if (_Geometries.Count == 0)
				return null;
			BoundingBox box = null;// _Geometries[0].GetBoundingBox();
			for (int i = 0; i < _Geometries.Count; i++)
				if (!_Geometries[i].IsEmpty())					
					box = box==null ? _Geometries[i].GetBoundingBox() : box.Join(_Geometries[i].GetBoundingBox());

			return box;
		}

		/// <summary>
		/// Gets the connection ID of the datasource
		/// </summary>
		/// <remarks>
		/// The ConnectionID is meant for Connection Pooling which doesn't apply to this datasource. Instead
		/// <c>String.Empty</c> is returned.
		/// </remarks>
		public string ConnectionID
		{
			get { return String.Empty; }
		}

		/// <summary>
		/// Opens the datasource
		/// </summary>
		public void Open()
		{
			//Do nothing;
		}

		/// <summary>
		/// Closes the datasource
		/// </summary>
		public void Close()
		{
			//Do nothing;
		}

		/// <summary>
		/// Returns true if the datasource is currently open
		/// </summary>
		public bool IsOpen
		{
			get { return true; }
		}

		#endregion

		private int _SRID = -1;
		/// <summary>
		/// The spatial reference ID (CRS)
		/// </summary>
		public int SRID
		{
			get { return _SRID; }
			set { _SRID = value; }
		}

		#region IDisposable Members

		/// <summary>
		/// Disposes the object
		/// </summary>
		public void Dispose()
		{
			_Geometries = null;
		}

		#endregion
	}
}