reproject_from_healpix

reproject.reproject_from_healpix(input_data, output_projection, shape_out=None, hdu_in=1, order='bilinear', nested=None, field=0)

Reproject data from a HEALPIX projection to a standard projection.

Parameters:

input_dataobject

The input data to reproject. This can be:

• The name of a HEALPIX FITS file

• A TableHDU or BinTableHDU instance

• A tuple where the first element is a ndarray and the second element is a BaseCoordinateFrame instance or a string alias for a coordinate frame.

output_projectionWCS or Header

The output projection, which can be either a WCS or a Header instance.

shape_outtuple, optional

If output_projection is a WCS instance, the shape of the output data should be specified separately.

hdu_inint or str, optional

If input_data is a FITS file, specifies the HDU to use. (the default HDU for HEALPIX data is 1, unlike with image files where it is generally 0).

orderint or str, optional

The order of the interpolation (if mode is set to 'interpolation'). This can be either one of the following strings:

• ‘nearest-neighbor’

• ‘bilinear’

or an integer. A value of 0 indicates nearest neighbor interpolation.

nestedbool, optional

The order of the healpix_data, either nested (True) or ring (False). If a FITS file is passed in, this is determined from the header.

fieldint, optional

The column to read from the HEALPIX FITS file. If the fits file is a partial-sky file, field=0 corresponds to the first column after the pixel index column.

Returns:

array_newndarray

The reprojected array.

footprintndarray

Footprint of the input array in the output array. Values of 0 indicate no coverage or valid values in the input image, while values of 1 indicate valid values.