skyview.geometry.projecter

Class Cah

java.lang.Object

skyview.geometry.Transformer

skyview.geometry.Projecter

skyview.geometry.projecter.Cah

All Implemented Interfaces:

java.io.Serializable, Component

public class Cah
extends Projecter

This class provides for the translation between coordinates and Cahill style Octahedron tangent plane projection. .

The projection is centered at 0,45 The projection is bounded by a rectangle with dimensions 6 sqrt(2) x 2 sqrt(6) which is filled in the following fashion. 5 4 2 3 5 5 4 4 2 2 3 3 5 5 5 4 4 4 2 2 2 3 3 3 5 5 4 4 6 0 2 2 3 3 5 4 6 6 0 0 2 3 6 6 6 0 0 0 7 6 6 0 0 1 7 7 6 0 1 1 7 7 7 1 1 1 7 7 1 1 7 1 Note that each number is intended to represent an equilateral triangle so that the representation here is only very approximate. The center of the projection is the middle of the boundary between triangles 0 and 6. The north pole is the intersection of triangles 0,2,4 and 6, while the south pole is at the lonely points of 1,3,5,7 The northern octants are even while the southern octants are odd. You can envisage this figure as unwrapping the four northern octants of an octahedron and pressing them flat and then flipping the southern octants on the equator they share with a northern octant. Note that this projection is staddleable but the straddle is not currently available.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	Cah.CahDeproj Deproject from the plane back to the unit sphere

Constructor Summary

Constructors

Constructor and Description
Cah()

Method Summary

Modifier and Type	Method and Description
java.lang.String	getDescription() Get the description of this component.
java.lang.String	getName() Get the name of this component.
Deprojecter	inverse() Get the inverse
boolean	isInverse(Transformer obj) Are these two transformations, inverses of each other? This method is used to optimize a series of transformations where transformations.
static void	main(java.lang.String[] args)
void	transform(double[] unit, double[] plane) Convert a single point where the output vector is supplied.

Methods inherited from class skyview.geometry.Projecter

allValid, getInputDimension, getOutputDimension, getXTiling, getYTiling, shadowPoint, straddle, straddleable, straddleComponents, tissot, validPosition

Methods inherited from class skyview.geometry.Transformer

transform, transform

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Cah

public Cah()

Method Detail

getName

public java.lang.String getName()

Description copied from interface: Component

Get the name of this component.

getDescription

public java.lang.String getDescription()

Description copied from interface: Component

Get the description of this component.

isInverse

public boolean isInverse(Transformer obj)

Description copied from class: Transformer

Are these two transformations, inverses of each other? This method is used to optimize a series of transformations where transformations.

Specified by:

isInverse in class Transformer

inverse

public Deprojecter inverse()

Description copied from class: Projecter

Get the inverse

Specified by:

inverse in class Projecter

transform

public void transform(double[] unit,
                      double[] plane)

Description copied from class: Transformer

Convert a single point where the output vector is supplied.

Specified by:

transform in class Transformer

Parameters:

unit - The input vector.

plane - The output vector, it may be the same as the input vector if the dimensionalities are the same. All transformers are expected to work with aliased inputs and output.

main

public static void main(java.lang.String[] args)
                 throws java.lang.Exception

Throws:

java.lang.Exception