spatialrelations.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 

using System;
using System.Collections.Generic;
using System.Text;

namespace SharpMap.Geometries
{
	/// <summary>
	/// Class defining a set of named spatial relationship operators for geometric shape objects.
	/// </summary>
	public class SpatialRelations
	{
		/// <summary>
		/// Returns true if otherGeometry is wholly contained within the source geometry. This is the same as
		/// reversing the primary and comparison shapes of the Within operation.
		/// </summary>
		/// <param name="sourceGeometry"></param>
		/// <param name="otherGeometry"></param>
		/// <returns>True if otherGeometry is wholly contained within the source geometry.</returns>
		public static bool Contains(Geometry sourceGeometry, Geometry otherGeometry)
		{
			return (otherGeometry.Within(sourceGeometry));
		}

		/// <summary>
		/// Returns true if the intersection of the two geometries results in a geometry whose dimension is less than
		/// the maximum dimension of the two geometries and the intersection geometry is not equal to either.
		/// geometry.
		/// </summary>
		/// <param name="g1"></param>
		/// <param name="g2"></param>
		/// <returns></returns>
		public static bool Crosses(Geometry g1, Geometry g2)
		{
			Geometry g = g2.Intersection(g1);
			return (g.Intersection(g1).Dimension < Math.Max(g1.Dimension, g2.Dimension) && !g.Equals(g1) && !g.Equals(g2));
		}

		/// <summary>
		/// Returns true if otherGeometry is disjoint from the source geometry.
		/// </summary>
		/// <param name="g1"></param>
		/// <param name="g2"></param>
		/// <returns></returns>
		public static bool Disjoint(Geometry g1, Geometry g2)
		{
			return !g2.Intersects(g1);
		}

		/// <summary>
		/// Returns true if otherGeometry is of the same type and defines the same point set as the source geometry.
		/// </summary>
		/// <param name="g1">source geometry</param>
		/// <param name="g2">other Geometry</param>
		/// <returns></returns>
		public static bool Equals(Geometry g1, Geometry g2)
		{
			if (g1 == null && g2 == null)
				return true;
			if (g1 == null || g2 == null)
				return false;
			if (g1.GetType() != g2.GetType())
				return false;
			if (g1 is SharpMap.Geometries.Point)
				return (g1 as Point).Equals(g2 as Point);
			else if (g1 is SharpMap.Geometries.LineString)
				return (g1 as LineString).Equals(g2 as LineString);
			else if (g1 is SharpMap.Geometries.Polygon)
				return (g1 as Polygon).Equals(g2 as Polygon);
			else if (g1 is SharpMap.Geometries.MultiPoint)
				return (g1 as MultiPoint).Equals(g2 as MultiPoint);
			else if (g1 is SharpMap.Geometries.MultiLineString)
				return (g1 as MultiLineString).Equals(g2 as MultiLineString);
			else if (g1 is SharpMap.Geometries.MultiPolygon)
				return (g1 as MultiPolygon).Equals(g2 as MultiPolygon);
			else
				throw new ArgumentException("The method or operation is not implemented on this geometry type.");
		}
		

		/// <summary>
		/// Returns true if there is any intersection between the two geometries.
		/// </summary>
		/// <param name="g1"></param>
		/// <param name="g2"></param>
		/// <returns></returns>
		public static bool Intersects(Geometry g1, Geometry g2)
		{
			throw new NotImplementedException();
		}

		/// <summary>
		/// Returns true if the intersection of the two geometries results in an object of the same dimension as the
		/// input geometries and the intersection geometry is not equal to either geometry.
		/// </summary>
		/// <param name="g1"></param>
		/// <param name="g2"></param>
		/// <returns></returns>
		public static bool Overlaps(Geometry g1, Geometry g2)
		{
			throw new NotImplementedException();
		}

		/// <summary>
		/// Returns true if the only points in common between the two geometries lie in the union of their boundaries.
		/// </summary>
		/// <param name="g1"></param>
		/// <param name="g2"></param>
		/// <returns></returns>
		public static bool Touches(Geometry g1, Geometry g2)
		{
			throw new NotImplementedException();
		}

		/// <summary>
		/// Returns true if the primary geometry is wholly contained within the comparison geometry.
		/// </summary>
		/// <param name="g1"></param>
		/// <param name="g2"></param>
		/// <returns></returns>
		public static bool Within(Geometry g1, Geometry g2)
		{
			return g1.Contains(g2);
		}
	}
}