DistortionLookupTable¶

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

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 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.

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).