astro
Class WcsModel

java.lang.Object
  vec_math.AbstractMultidimensionalDataModel
      astro.WcsModel

All Implemented Interfaces:

MultidimensionalDataModel

public class WcsModel
extends AbstractMultidimensionalDataModel

A mapping of pixel coordinates to WCS coordinates, ICRS 2000 right ascension and declination in almost any possible case. Note that independant and dependant coordinates have the same dimension (2-dim vectors) and thus can be exchanged likewise. In normal mode, one wants to get from the image coordinates (pixels) to α, δ, thus we solve for the parameters that convert x/y (independent, first constructor argument) to ra/de (dependant, second constructor argument). If you want to use errors at all, be aware that errors in the determination of x/y have to be converted to ra/de errors in this standard case. It is normally sufficient to devide the dx dy by the plate scale to get to d(ra), d(de), but generally speaking a solution should also be obtainable without errors to be considered.

Field Summary

private WcsProjection

wcs The WCS projection that converts pixel to ra/de.

Fields inherited from class vec_math.AbstractMultidimensionalDataModel

sigma, x, y

Constructor Summary

WcsModel(VectorG[] xy, VectorG[] rade)
We construct the model using the measured pixel coordinates and the matched catalog ra de.

WcsModel(VectorG[] xy, VectorG[] rade, WcsProjection using)
We construct the model using the measured pixel coordinates and the matched catalog ra de.

Method Summary

VectorG	evaluateModel(VectorG params, VectorG pixel) We evaluate the WCS model for the given parameters and the pixel position.
int	getParameterCount() The parameter count is the parameter count from the projection.
WcsProjection	getProjection() Returns the projection used by this model.

Methods inherited from class vec_math.AbstractMultidimensionalDataModel

dimension, equalData, getChiSquareModel, getChiSquareModel, getLorentzianModel, getMeasureCount, getMeasurementErrors, getMeasures, getModel, getModel, getResiduals, getResiduals, getRobustModel, getTimes, getTotalErrors, simplexChiSquareSolve, simplexChiSquareSolve, simplexLorentzSolve, simplexLorentzSolve, simplexRobustSolve, simplexRobustSolve

Methods inherited from class java.lang.Object

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

Field Detail

wcs

private WcsProjection wcs

The WCS projection that converts pixel to ra/de.

Constructor Detail

WcsModel

public WcsModel(VectorG[] xy,
                VectorG[] rade)

We construct the model using the measured pixel coordinates and the matched catalog ra de. Each pixel pair must corespond to a catalog pair.

WcsModel

public WcsModel(VectorG[] xy,
                VectorG[] rade,
                WcsProjection using)

We construct the model using the measured pixel coordinates and the matched catalog ra de. Each pixel pair must corespond to a catalog pair.

Method Detail

getParameterCount

public int getParameterCount()

The parameter count is the parameter count from the projection.

Returns:

The number of parameters in the model. This equals the dimension of the input vector in MultidimensionalDataModel.getModel(vec_math.VectorG).

evaluateModel

public VectorG evaluateModel(VectorG params,
                             VectorG pixel)

We evaluate the WCS model for the given parameters and the pixel position.

Parameters:

params - The model parameters

pixel - The vector of independant variables.

getProjection

public WcsProjection getProjection()

Returns the projection used by this model.