24 from ._geom
import SipApproximation, getPixelToIntermediateWorldCoords
25 from ._geom
import makeTanSipMetadata
27 __all__ = (
"calculateSipWcsHeader",)
31 """Generate a SIP WCS header approximating a given ``SkyWcs``
35 wcs : `lsst.afw.geom.SkyWcs`
36 World Coordinate System to approximate as SIP.
38 SIP order (equal to the maximum sum of the polynomial exponents).
39 bbox : `lsst.geom.Box2I`
40 Bounding box over which to approximate the ``wcs``.
42 Spacing between sample points.
43 header : `lsst.daf.base.PropertyList`, optional
44 Header to which to add SIP WCS keywords.
48 header : `lsst.daf.base.PropertyList`
49 Header including SIP WCS keywords.
53 >>> header = calculateSipWcsHeader(exposure.getWcs(), 3, exposure.getBBox(), 20)
54 >>> sipWcs = SkyWcs(header)
57 crpix = wcs.getPixelOrigin()
58 cdMatrix = wcs.getCdMatrix()
59 crval = wcs.getSkyOrigin()
60 gridNum =
Extent2I(int(bbox.getWidth()/spacing + 0.5), int(bbox.getHeight()/spacing + 0.5))
62 sip = SipApproximation(transform, crpix, cdMatrix,
Box2D(bbox), gridNum, order)
64 md =
makeTanSipMetadata(sip.getPixelOrigin(), crval, sip.getCdMatrix(), sip.getA(), sip.getB(),
65 sip.getAP(), sip.getBP())
67 if header
is not None:
std::shared_ptr< TransformPoint2ToPoint2 > getPixelToIntermediateWorldCoords(SkyWcs const &wcs, bool simplify=true)
Return a transform from pixel coordinates to intermediate world coordinates.
std::shared_ptr< daf::base::PropertyList > makeTanSipMetadata(lsst::geom::Point2D const &crpix, lsst::geom::SpherePoint const &crval, Eigen::Matrix2d const &cdMatrix, Eigen::MatrixXd const &sipA, Eigen::MatrixXd const &sipB)
Make metadata for a TAN-SIP WCS without inverse matrices.