Geotools.Net

IMathTransformFactory Interface

Creates math transforms.

For a list of all members of this type, see IMathTransformFactory Members.

[Visual Basic]
Public Interface IMathTransformFactory
[C#]
public interface IMathTransformFactory

Remarks

IMathTransformFactory is a low level factory that is used to create IMathTransform objects. Many high level GIS applications will never need to use a IMathTransformFactory directly; they can use a ICoordinateTransformationFactory instead. However, the IMathTransformFactory 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).

The following comments assume that the same vendor implements the math transform factory interfaces and math transform interfaces.

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 IMathTransformFactory significantly easier than it would be otherwise.

For example IMathTransformFactory 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.

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 IMathTransformFactory.

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.

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.

Requirements

Namespace: Geotools.CoordinateTransformations Namespace

Assembly: Geotools.dll

See Also

IMathTransformFactory Members | Geotools.CoordinateTransformations Namespace