calculateSipWcsHeader

lsst.afw.geom.calculateSipWcsHeader(wcs, order, bbox, spacing, header=None)

Generate a SIP WCS header approximating a given SkyWcs

Parameters:

wcs : lsst.afw.geom.SkyWcs

World Coordinate System to approximate as SIP.

order : int

SIP order (equal to the maximum sum of the polynomial exponents).

bbox : lsst.geom.Box2I

Bounding box over which to approximate the wcs.

spacing : float

Spacing between sample points.

header : lsst.daf.base.PropertyList, optional

Header to which to add SIP WCS keywords.

Returns:

header : lsst.daf.base.PropertyList

Header including SIP WCS keywords.

Examples

>>> header = calculateSipWcsHeader(exposure.getWcs(), 3, exposure.getBBox(), 20)
>>> sipWcs = SkyWcs(header)