// 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.Collections.Generic;
namespace GeoAPI.CoordinateSystems.Transformations{
/// <summary>
/// Creates math transforms.
/// </summary>
/// <remarks>
/// <para>CT_MathTransformFactory is a low level factory that is used to create CT_MathTransform objects. Many high level GIS applications will never need to use a CT_MathTransformFactory directly; they can use a CT_CoordinateTransformationFactory instead. However, the CT_MathTransformFactory interface is specified here, since it can be used directly by applications that wish to transform other types of coordinates (e.g. color coordinates, or image pixel coordinates).</para>
/// <para>The following comments assume that the same vendor implements the math transform factory interfaces and math transform interfaces.</para>
/// <para>A math transform is an object that actually does the work of applying formulae to coordinate values. The math transform does not know or care how the coordinates relate to positions in the real world. This lack of semantics makes implementing CT_MathTransformFactory significantly easier than it would be otherwise.</para>
/// <para>For example CT_MathTransformFactory can create affine math transforms. The affine transform applies a matrix to the coordinates without knowing how what it is doing relates to the real world. So if the matrix scales Z values by a factor of 1000, then it could be converting meters into millimeters, or it could be converting kilometers into meters.</para>
/// <para>Because math transforms have low semantic value (but high mathematical value), programmers who do not have much knowledge of how GIS applications use coordinate systems, or how those coordinate systems relate to the real world can implement CT_MathTransformFactory.</para>
/// <para>The low semantic content of math transforms also means that they will be useful in applications that have nothing to do with GIS coordinates. For example, a math transform could be used to map color coordinates between different color spaces, such as converting (red, green, blue) colors into (hue, light, saturation) colors.</para>
/// <para>Since a math transform does not know what its source and target coordinate systems mean, it is not necessary or desirable for a math transform object to keep information on its source and target coordinate systems.</para>
/// </remarks>
public interface IMathTransformFactory
{
/// <summary>
/// Creates an affine transform from a matrix.
/// </summary>
/// <remarks>If the transform's input dimension is M, and output dimension is N, then the matrix will have size [N+1][M+1]. The +1 in the matrix dimensions allows the matrix to do a shift, as well as a rotation. The [M][j] element of the matrix will be the j'th ordinate of the moved origin. The [i][N] element of the matrix will be 0 for i less than M, and 1 for i equals M.</remarks>
/// <param name="matrix"></param>
/// <returns></returns>
IMathTransform CreateAffineTransform(double[,] matrix);
/// <summary>
/// Creates a transform by concatenating two existing transforms. A concatenated transform acts in the same way as applying two transforms, one after the other.
/// </summary>
/// <remarks>The dimension of the output space of the first transform must match the dimension of the input space in the second transform. If you wish to concatenate more than two transforms, then you can repeatedly use this method.</remarks>
/// <param name="transform1"></param>
/// <param name="transform2"></param>
/// <returns></returns>
IMathTransform CreateConcatenatedTransform(IMathTransform transform1, IMathTransform transform2);
/// <summary>
/// Creates a math transform from a Well-Known Text string.
/// </summary>
/// <param name="wkt"></param>
/// <returns></returns>
IMathTransform CreateFromWKT(string wkt);
/// <summary>
/// Creates a math transform from XML.
/// </summary>
/// <param name="xml"></param>
/// <returns></returns>
IMathTransform CreateFromXML(string xml);
/// <summary>
/// Creates a transform from a classification name and parameters.
/// </summary>
/// <remarks>
/// The client must ensure that all the linear parameters are expressed in meters, and all the angular parameters are expressed in degrees. Also, they must supply "semi_major" and "semi_minor" parameters for cartographic projection transforms.
/// </remarks>
/// <param name="classification"></param>
/// <param name="parameters"></param>
/// <returns></returns>
IMathTransform CreateParameterizedTransform(string classification, List<Parameter> parameters);
/// <summary>
/// Creates a transform which passes through a subset of ordinates to another transform.
/// </summary>
/// <remarks>
/// This allows transforms to operate on a subset of ordinates. For example, if you have (Lat,Lon,Height) coordinates, then you may wish to convert the height values from meters to feet without affecting the (Lat,Lon) values. If you wanted to affect the (Lat,Lon) values and leave the Height values alone, then you would have to swap the ordinates around to (Height,Lat,Lon). You can do this with an affine map.
/// </remarks>
/// <param name="firstAffectedOrdinate"></param>
/// <param name="subTransform"></param>
/// <returns></returns>
IMathTransform CreatePassThroughTransform(int firstAffectedOrdinate, IMathTransform subTransform);
/// <summary>
/// Tests whether parameter is angular. Clients must ensure that all angular parameter values are in degrees.
/// </summary>
/// <param name="parameterName"></param>
/// <returns></returns>
bool IsParameterAngular(string parameterName);
/// <summary>
/// Tests whether parameter is linear. Clients must ensure that all linear parameter values are in meters.
/// </summary>
/// <param name="parameterName"></param>
/// <returns></returns>
bool IsParameterLinear(string parameterName);
}
}
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