DistortionLookupTable

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

Bases: object

Represents a single lookup table for a distortion paper transformation.

Parameters:

table : 2-dimensional array

The distortion lookup table.

crpix : 2-tuple

The distortion array reference pixel

crval : 2-tuple

The image array pixel coordinate

cdelt : 2-tuple

The grid step size

Attributes Summary

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

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) -> (x, y)

Returns the offset as defined in the distortion lookup table.

Returns:

coordinate : coordinate pair

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