lsst.meas.astrom.astrom Namespace Reference

Classes
class	InitialAstrometry
class	Astrometry

Functions
def	_createMetadata
def	readMatches

Function Documentation

def lsst.meas.astrom.astrom._createMetadata (   width,   height,   x0,   y0,   wcs,   filterName  )

private

Create match metadata entries required for regenerating the catalog

@param width Width of the image (pixels)
@param height Height of the image (pixels)
@param x0 x offset of image origin from parent (pixels)
@param y0 y offset of image origin from parent (pixels)
@param filterName Name of filter, used for magnitudes
@return Metadata

Definition at line 1098 of file astrom.py.

def _createMetadata(width, height, x0, y0, wcs, filterName):
    """
    Create match metadata entries required for regenerating the catalog

    @param width Width of the image (pixels)
    @param height Height of the image (pixels)
    @param x0 x offset of image origin from parent (pixels)
    @param y0 y offset of image origin from parent (pixels)
    @param filterName Name of filter, used for magnitudes
    @return Metadata
    """
    meta = dafBase.PropertyList()

    # cache: field center and size.
    cx,cy = x0 + 0.5 + width/2., y0 + 0.5 + height/2.
    radec = wcs.pixelToSky(cx, cy).toIcrs()
    meta.add('RA', radec.getRa().asDegrees(), 'field center in degrees')
    meta.add('DEC', radec.getDec().asDegrees(), 'field center in degrees')
    imgSize = wcs.pixelScale() * math.hypot(width, height)/2.
    meta.add('RADIUS', imgSize.asDegrees(),
             'field radius in degrees, approximate')
    meta.add('SMATCHV', 1, 'SourceMatchVector version number')
    if filterName is not None:
        meta.add('FILTER', filterName, 'LSST filter name for tagalong data')
    return meta