lsst.skymap.detail.utils Namespace Reference

Classes
class	Index2D

Functions
	coordFromVec (vec, defRA=None)
	makeSkyPolygonFromBBox (bbox, wcs)

Variables
	_TinyFloat = numpy.finfo(float).tiny

Function Documentation

coordFromVec()

lsst.skymap.detail.utils.coordFromVec	(		vec,
			defRA = None )

Convert an ICRS cartesian vector to an ICRS `lsst.geom.SpherePoint`.

Parameters
----------
vec : `list` of `float`
    An ICRS catesian vector.
defRA : `lsst.geom.Angle` or None
    The RA to use if the vector is too near a pole;
    ignored if not near a pole.

Raises
------
RuntimeError
    Raised if vec too near a pole and defRA is None.

Definition at line 34 of file utils.py.

def coordFromVec(vec, defRA=None):
    """Convert an ICRS cartesian vector to an ICRS `lsst.geom.SpherePoint`.
 
    Parameters
    ----------
    vec : `list` of `float`
        An ICRS catesian vector.
    defRA : `lsst.geom.Angle` or None
        The RA to use if the vector is too near a pole;
        ignored if not near a pole.
 
    Raises
    ------
    RuntimeError
        Raised if vec too near a pole and defRA is None.
    """
    if abs(vec[0]) < _TinyFloat and abs(vec[1]) < _TinyFloat:
        if defRA is None:
            raise RuntimeError("At pole and defRA==None")
        if vec[2] > 0:
            decDeg = 90.0
        else:
            decDeg = -90.0
        return geom.SpherePoint(defRA, decDeg*geom.degrees)
    return geom.SpherePoint(lsst.sphgeom.Vector3d(*vec))
 
 

makeSkyPolygonFromBBox()

lsst.skymap.detail.utils.makeSkyPolygonFromBBox	(		bbox,
			wcs )

Make an on-sky polygon from a bbox and a SkyWcs.

Parameters
----------
bbox : `lsst.geom.Box2I` or `lsst.geom.Box2D`
    Bounding box of region, in pixel coordinates.
wcs : `lsst.afw.geom.SkyWcs`
    Celestial WCS.

Returns
-------
polygon : `lsst.sphgeom.ConvexPolygon`
    On-sky region

Definition at line 61 of file utils.py.

def makeSkyPolygonFromBBox(bbox, wcs):
    """Make an on-sky polygon from a bbox and a SkyWcs.
 
    Parameters
    ----------
    bbox : `lsst.geom.Box2I` or `lsst.geom.Box2D`
        Bounding box of region, in pixel coordinates.
    wcs : `lsst.afw.geom.SkyWcs`
        Celestial WCS.
 
    Returns
    -------
    polygon : `lsst.sphgeom.ConvexPolygon`
        On-sky region
    """
    pixelPoints = geom.Box2D(bbox).getCorners()
    skyPoints = wcs.pixelToSky(pixelPoints)
    return lsst.sphgeom.ConvexPolygon([sp.getVector() for sp in skyPoints])
 
 

Variable Documentation

_TinyFloat

lsst.skymap.detail.utils._TinyFloat = numpy.finfo(float).tiny

protected

Definition at line 31 of file utils.py.