- HSTWCS class was modified to

  - not keep the headers as attributes
  - accept an adittional paramter fobj, consistent with SIP and WCS classes.
  - The restore method was renamed to get_archive and moved to utils
- corrections classes:
  - updateWCS were turned into classmethods
  - diff_abgles was moved to utils
- restoreWCS() was moved to utils





git-svn-id: http://svn.stsci.edu/svn/ssb/stsci_python/development/trunk/hstwcs@6973 fe389314-cf27-0410-b35b-8c050e845b92

1 files changed, 83 insertions, 0 deletions

diff --git a/lib/utils.py b/lib/utils.py
new file mode 100644
index 0000000..bec12f7
--- /dev/null
+++ b/lib/utils.py
@@ -0,0 +1,83 @@
+from pytools import parseinput, fileutil
+import pyfits
+from mappings import basic_wcs
+
+def restoreWCS(fnames):
+    """
+    Given a list of fits file names restore the original basic WCS kw
+    and write out the files. This overwrites the original files.
+    
+    Affected keywords:
+    'CD1_1', 'CD1_2', 'CD2_1', 'CD2_2', 'CRVAL1','CRVAL2','CTYPE1', 'CTYPE2',
+    'CRPIX1', 'CRPIX2', 'CTYPE1', 'CTYPE2', 'ORIENTAT'
+    """
+    files = parseinput.parseinput(fnames)[0]
+    for f in files:
+        isfits, ftype = fileutil.isFits(f)
+        if not isfits or (isfits and ftype == 'waiver'):
+            print "RestoreWCS works only with true fits files."
+            return
+        else:
+            fobj = pyfits.open(f, mode='update')
+            for ext in fobj:
+                try:
+                    extname = ext.header['EXTNAME'].lower()
+                except KeyError:
+                    continue
+                if extname in ['sci', 'err', 'sdq']:
+                    hdr = ext.header
+                    backup = get_archive(hdr)
+                    if not backup:
+                        #print 'No archived keywords found.\n'
+                        continue
+                    else:
+                        for kw in basic_wcs:
+                            nkw = ('O'+kw)[:7]
+                            if backup.has_key(kw):
+                                hdr.update(kw, hdr[nkw])
+            fobj.close()
+
+def get_archive(header):
+    """
+    Returns a dictionary with the archived basic WCS keywords.
+    """    
+
+    backup = {}
+    for k in basic_wcs:
+        try:
+            nkw = ('O'+k)[:7]
+            backup[k] = header[nkw]
+        except KeyError:
+            pass
+    return backup
+    
+def write_archive(header):
+    """
+    Archives original WCS kw before recalculating them.
+    """
+    backup_kw = get_archive(header)
+    if backup_kw != {}:
+        print "Archive already exists\n."
+        return
+    else:
+        cmt = 'archived value'
+        for kw in basic_wcs:
+            nkw = 'O'+kw
+            header.update(nkw[:7], header[kw], comment=cmt)
+    
+
+def diff_angles(a,b):
+    """ 
+    Perform angle subtraction a-b taking into account
+    small-angle differences across 360degree line. 
+    """
+    
+    diff = a - b
+
+    if diff > 180.0:
+       diff -= 360.0
+
+    if diff < -180.0:
+       diff += 360.0
+    
+    return diff
\ No newline at end of file