diff options
| -rw-r--r-- | lib/stwcs/wcsutil/headerlet.py | 35 |
1 files changed, 25 insertions, 10 deletions
diff --git a/lib/stwcs/wcsutil/headerlet.py b/lib/stwcs/wcsutil/headerlet.py index 99a7fe3..d85d6b2 100644 --- a/lib/stwcs/wcsutil/headerlet.py +++ b/lib/stwcs/wcsutil/headerlet.py @@ -1,13 +1,12 @@ """ This module implements headerlets. -A headerlet serves as a mechanism for encapsulating WCS information -which can be used to update the WCS solution of an image. The idea -came up first from the desire for passing improved astrometric -solutions for HST data and provide those solutions in a manner -that would not require getting entirely new images from the archive -when only the WCS information has been updated. - +A headerlet is a representation of a single WCS solution for a single exposure +complete with all distortion information. FITS is the data storage format +currently supported. It has no observational data which makes it relatively +small and light to distribute. This is different from alternate WCS defined in +Paper I in that by definition all alternate WCSs share the same distortion model +while headerlets may be based on different distortion models. """ from __future__ import division @@ -181,7 +180,7 @@ def get_headerlet_kw_names(fobj, kw='HDRNAME'): fobj.close() return hdrnames - +""" def get_header_kw_vals(hdr, kwname, kwval, default=0): if kwval is None: if kwname in hdr: @@ -189,7 +188,7 @@ def get_header_kw_vals(hdr, kwname, kwval, default=0): else: kwval = default return kwval - +""" @with_logging def find_headerlet_HDUs(fobj, hdrext=None, hdrname=None, distname=None, @@ -458,7 +457,9 @@ def update_ref_files(source, dest): Parameters ---------- source: pyfits.Header + source file dest: pyfits.Header + destination file """ logger.info("Updating reference files") phdukw = {'NPOLFILE': True, @@ -2320,6 +2321,12 @@ class Headerlet(pyfits.HDUList): return dname def equal_distmodel(self, dmodel): + """ + Verify if headerlet distortion model is the same as dmodel + + dmodel: string + value of keyword DISTNAME + """ if dmodel != self[0].header['DISTNAME']: if self.logging: message = """ @@ -2578,6 +2585,13 @@ def _idc2hdr(fromhdr, tohdr, towkey=' '): """ Copy the IDC (HST specific) keywords from one header to another + fromhdr: pyfits.Header + source header + toheader: pyfits.Header + destination header + towkey: string, 'A', ..., 'Z' + key for alternate WCS + """ # save some of the idc coefficients coeffs = ['OCX10', 'OCX11', 'OCY10', 'OCY11', 'IDCSCALE'] @@ -2594,8 +2608,9 @@ def get_extname_extver_list(fobj, sciext): Create a list of (EXTNAME, EXTVER) tuples Based on sciext keyword (see docstring for create_headerlet) - walk throughh the file and convert extensions in `sciext` to + walk through the file and convert extensions in `sciext` to valid (EXTNAME, EXTVER) tuples. + """ extlist = [] if isinstance(sciext, int): |