// 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
namespace GeoAPI.CoordinateSystems{
/// <summary>
/// Base interface for all coordinate systems
/// </summary>
/// <remarks>
/// <para>A coordinate system is a mathematical space, where the elements of the space are called
/// positions. Each position is described by a list of numbers. The length of the list corresponds
/// to the dimension of the coordinate system. So in a 2D coordinate system each position is
/// described by a list containing 2 numbers.</para>
/// <para>
/// However, in a coordinate system, not all lists of numbers correspond to a position -
/// some lists may be outside the domain of the coordinate system. For example, in a 2D Lat/Lon
/// coordinate system, the list (91,91) does not correspond to a position.</para>
/// <para>
/// Some coordinate systems also have a mapping from the mathematical space into locations
/// in the real world. So in a Lat/Lon coordinate system, the mathematical position (lat, long)
/// corresponds to a location on the surface of the Earth. This mapping from the mathematical
/// space into real-world locations is called a Datum.</para>
/// </remarks>
public interface ICoordinateSystem : IInfo
{
/// <summary>
/// Dimension of the coordinate system.
/// </summary>
int Dimension { get; }
/// <summary>
/// Gets axis details for dimension within coordinate system.
/// </summary>
/// <param name="dimension">Dimension</param>
/// <returns>Axis info</returns>
AxisInfo GetAxis(int dimension);
/// <summary>
/// Gets units for dimension within coordinate system.
/// </summary>
IUnit GetUnits(int dimension);
/// <summary>
/// Gets default envelope of coordinate system.
/// </summary>
/// <remarks>
/// Gets default envelope of coordinate system. Coordinate systems
/// which are bounded should return the minimum bounding box of their
/// domain. Unbounded coordinate systems should return a box which is
/// as large as is likely to be used. For example, a (lon,lat)
/// geographic coordinate system in degrees should return a box from
/// (-180,-90) to (180,90), and a geocentric coordinate system could
/// return a box from (-r,-r,-r) to (+r,+r,+r) where r is the
/// approximate radius of the Earth.
/// </remarks>
double[] DefaultEnvelope { get; }
}
}
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