curve.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>
	/// A Curve is a one-dimensional geometric object usually stored as a sequence of points,
	/// with the subtype of Curve specifying the form of the interpolation between points.
	/// </summary>
	public abstract class Curve : Geometry
	{
		/// <summary>
		///  The inherent dimension of this Geometry object, which must be less than or equal to the coordinate dimension.
		/// </summary>
		public override int Dimension
		{
			get { return 1; }
		}
		/// <summary>
		/// The length of this Curve in its associated spatial reference.
		/// </summary>
		public abstract double Length { get; }
		/// <summary>
		/// The start point of this Curve.
		/// </summary>
		public abstract Point StartPoint { get; }
		/// <summary>
		/// The end point of this Curve.
		/// </summary>
		public abstract Point EndPoint { get; }
		/// <summary>
		/// The position of a point on the line, parameterised by length.
		/// </summary>
		/// <param name="t"></param>
		/// <returns></returns>
		public abstract Point Value(double t);
		/// <summary>
		/// Returns true if this Curve is closed (StartPoint = EndPoint).
		/// </summary>
		public bool IsClosed
		{
			get { return (this.StartPoint.Equals(this.EndPoint)); }
		}
		/// <summary>
		/// true if this Curve is closed (StartPoint = EndPoint) and
		/// this Curve is simple (does not pass through the same point more than once).
		/// </summary>
		public abstract bool IsRing { get; }
	}
}