SIP

class astropy.modeling.polynomial.SIP(crpix, a_order, b_order, a_coeff={}, b_coeff={}, ap_order=None, bp_order=None, ap_coeff={}, bp_coeff={}, n_models=None, model_set_axis=None)

Bases: astropy.modeling.Model

Simple Imaging Polynomial (SIP) model.

The SIP convention is used to represent distortions in FITS image headers. See [R9] for a description of the SIP convention.

Parameters:

crpix : list or ndarray of length(2)

CRPIX values

a_order : int

SIP polynomial order for first axis

b_order : int

SIP order for second axis

a_coeff : dict

SIP coefficients for first axis

b_coeff : dict

SIP coefficients for the second axis

ap_order : int

order for the inverse transformation (AP coefficients)

bp_order : int

order for the inverse transformation (BP coefficients)

ap_coeff : dict

coefficients for the inverse transform

bp_coeff : dict

coefficients for the inverse transform

param_dim : int

number of parameter sets

References

[R9]	(1, 2) David Shupe, et al, ADASS, ASP Conference Series, Vol. 347, 2005

Attributes Summary

input_names	list() -> new empty list
n_inputs	int(x=0) -> int or long
n_outputs	int(x=0) -> int or long

Methods Summary

evaluate(x, y)
inverse()

Attributes Documentation

input_names = []

n_inputs = 2

n_outputs = 2

Methods Documentation

evaluate(x, y)

inverse()