DistortionLookupTable

class astropy.wcs.DistortionLookupTable(table, crpix, crval, cdelt)

Bases: object

Represents a single lookup table for a distortion paper transformation.

Parameters:

table2-dimensional array

The distortion lookup table.

crpix2-tuple

The distortion array reference pixel, in FITS Header format: 1-based indexing, (x,y) order.

crval2-tuple

The image array pixel coordinate, in FITS Header format: 1-based indexing, (x,y) order.

cdelt2-tuple

The grid step size

Attributes Summary

cdelt	double array[naxis] Coordinate increments (CDELTia) for each coord axis.
crpix	double array[naxis] Coordinate reference pixels (CRPIXja) for each pixel axis.
crval	double array[naxis] Coordinate reference values (CRVALia) for each coordinate axis.
data	float array The array data for the DistortionLookupTable.

Methods Summary

get_offset(x, y)

Returns the offset as defined in the distortion lookup table.

Attributes Documentation

cdelt

double array[naxis] Coordinate increments (CDELTia) for each coord axis.

If a CDi_ja linear transformation matrix is present, a warning is raised and cdelt is ignored. The CDi_ja matrix may be deleted by:

del wcs.wcs.cd

An undefined value is represented by NaN.

crpix

double array[naxis] Coordinate reference pixels (CRPIXja) for each pixel axis.

crval

double array[naxis] Coordinate reference values (CRVALia) for each coordinate axis.

data

float array The array data for the DistortionLookupTable.

Methods Documentation

get_offset(x, y)

Returns the offset as defined in the distortion lookup table.

Returns:

coordinate(2,) python:tuple

The offset from the distortion table for pixel point (x, y).