Approximate an existing WCS as a TAN-SIP WCS
The fit is performed by evaluating the WCS at a uniform grid of points
within a bounding box.
Parameters
----------
wcs : `lsst.afw.geom.SkyWcs`
wcs to approximate
bbox : `lsst.geom.Box2I`
the region over which the WCS will be fit
order : `int`
order of SIP fit
nx : `int`
number of grid points along x
ny : `int`
number of grid points along y
iterations : `int`
number of times to iterate over fitting
skyTolerance : `lsst.geom.Angle`
maximum allowed difference in world coordinates between
input wcs and approximate wcs (default is 0.001 arcsec)
pixelTolerance : `float`
maximum allowed difference in pixel coordinates between
input wcs and approximate wcs (default is 0.02 pixels)
useTanWcs : `bool`
send a TAN version of wcs to the fitter? It is documented to require that,
but I don't think the fitter actually cares
Returns
-------
fitWcs : `lsst.afw.geom.SkyWcs`
the fit TAN-SIP WCS
Definition at line 43 of file approximateWcs.py.