C# Class SharpMap.CoordinateSystems.Transformations.MathTransform

Gets the derivative of this transform at a point. If the transform does not have a well-defined derivative at the point, then this function should fail in the usual way for the DCP. The derivative is the matrix of the non-translating portion of the approximate affine map at the point. The matrix will have dimensions corresponding to the source and target coordinate systems. If the input dimension is M, and the output dimension is N, then the matrix will have size [M][N]. The elements of the matrix {elt[n][m] : n=0..(N-1)} form a vector in the output space which is parallel to the displacement caused by a small change in the m'th ordinate in the input space.

Gets transformed convex hull.

The supplied ordinates are interpreted as a sequence of points, which generates a convex hull in the source space. The returned sequence of ordinates represents a convex hull in the output space. The number of output points will often be different from the number of input points. Each of the input points should be inside the valid domain (this can be checked by testing the points' domain flags individually). However, the convex hull of the input points may go outside the valid domain. The returned convex hull should contain the transformed image of the intersection of the source convex hull and the source domain.

A convex hull is a shape in a coordinate system, where if two positions A and B are inside the shape, then all positions in the straight line between A and B are also inside the shape. So in 3D a cube and a sphere are both convex hulls. Other less obvious examples of convex hulls are straight lines, and single points. (A single point is a convex hull, because the positions A and B must both be the same - i.e. the point itself. So the straight line between A and B has zero length.)

Some examples of shapes that are NOT convex hulls are donuts, and horseshoes.

Gets flags classifying domain points within a convex hull.

The supplied ordinates are interpreted as a sequence of points, which generates a convex hull in the source space. Conceptually, each of the (usually infinite) points inside the convex hull is then tested against the source domain. The flags of all these tests are then combined. In practice, implementations of different transforms will use different short-cuts to avoid doing an infinite number of tests.

Tests whether this transform does not move any points.

Creates the inverse transform of this object.

This method may fail if the transform is not one to one. However, all cartographic projections should succeed.

Reverses the transformation

Transforms a coordinate point. The passed parameter point should not be modified.

Transforms a list of coordinate point ordinal values.

This method is provided for efficiently transforming many points. The supplied array of ordinal values will contain packed ordinal values. For example, if the source dimension is 3, then the ordinals will be packed in this order (x0,y0,z0,x1,y1,z1 ...). The size of the passed array must be an integer multiple of DimSource. The returned ordinal values are packed in a similar way. In some DCPs. the ordinals may be transformed in-place, and the returned array may be the same as the passed array. So any client code should not attempt to reuse the passed ordinal values (although they can certainly reuse the passed array). If there is any problem then the server implementation will throw an exception. If this happens then the client should not make any assumptions about the state of the ordinal values.

To convert degrees to radians, multiply degrees by pi/180.