- If idc table is not found and idc model cannot be restored from SIP, idcmodel is always set to None.

- Two cases are considered when output_wcs is created and idcmodel for the reference image is None:
-- if idcmodel can be found, a RuntimeError will be raised and the user prompted to run 'updatewcs' or pass 'undistort=False' kw.
-- if idcmodel cannot be found, the original WCS for the reference object will be returned and used as an output WCS.



git-svn-id: http://svn.stsci.edu/svn/ssb/stsci_python/stsci_python/trunk/stwcs@8640 fe389314-cf27-0410-b35b-8c050e845b92

4 files changed, 71 insertions, 31 deletions

diff --git a/distortion/coeff_converter.py b/distortion/coeff_converter.py
index 807bc3f..f2eb4ad 100644
--- a/distortion/coeff_converter.py
+++ b/distortion/coeff_converter.py
@@ -16,12 +16,11 @@ def sip2idc(wcs):
         ocx11 = wcs.get('OCX11', None)
         ocy10 = wcs.get('OCY10', None)
         ocy11 = wcs.get('OCY11', None)
-        order = hdr.get('A_ORDER', None)
-        sipa, sipb = _read_sip_kw(header)
-        if sipa == None or sipb == None:
-            print 'SIP coefficients are not available.\n'
+        order = wcs.get('A_ORDER', None)
+        sipa, sipb = _read_sip_kw(wcs)
+        if None in [ocx10, ocx11, ocy10, ocy11, sipa, sipb]:
             print 'Cannot convert SIP to IDC coefficients.\n'
-            return
+            return None, None
     elif isinstance(wcs,pywcs.WCS):
         try:
             ocx10 = wcs.ocx10
@@ -31,27 +30,28 @@ def sip2idc(wcs):
         except AttributeError:
             print 'First order IDCTAB coefficients are not available.\n'
             print 'Cannot convert SIP to IDC coefficients.\n'
-            return
+            return None, None
         try:
             sipa = wcs.sip.a
             sipb = wcs.sip.b
         except AttributeError:
-            print 'SIP coefficients are not available.\n'
+            print 'SIP coefficients are not available.'
             print 'Cannot convert SIP to IDC coefficients.\n'
-            return
+            return None, None
+        try:
+            order = wcs.sip.a_order
+        except AttributeError:
+            print 'SIP model order unknown, exiting ...\n'
+            return None, None
+
     else:
         print 'Input to sip2idc must be a PyFITS header or a wcsutil.HSTWCS object\n'
         return
     
-    try:
-        order = wcs.sip.a_order
-    except AttributeError:
-        print 'SIP model order unknown, exiting ...\n'
-        return
-
+    
     if None in [ocx10, ocx11, ocy10, ocy11]:
         print 'First order IDC coefficients not found, exiting ...\n'
-        return
+        return 
     idc_coeff = np.array([[ocx11, ocx10], [ocy11, ocy10]])
     cx = np.zeros((order+1,order+1), dtype=np.double)
     cy = np.zeros((order+1,order+1), dtype=np.double)
@@ -102,6 +102,8 @@ def _read_sip_kw(header):
         b = None
             
     return a , b
+
+
 """
 def idc2sip(wcsobj, idctab = None):
     if isinstance(wcs,pywcs.WCS):
diff --git a/distortion/utils.py b/distortion/utils.py
index 06bf5f8..bc25daf 100644
--- a/distortion/utils.py
+++ b/distortion/utils.py
@@ -1,9 +1,11 @@
 from __future__ import division # confidence high 
+import os 
 import numpy as np
 import pywcs
 import pyfits
 from stwcs import wcsutil
 from numpy import sqrt, arctan2
+from pytools import fileutil
 
 def output_wcs(list_of_wcsobj, ref_wcs=None, outwcs=None, undistort=True):
     fra_dec = np.vstack([w.calcFootprint() for w in list_of_wcsobj])
@@ -52,6 +54,18 @@ def  undistortWCS(wcsobj):
     import coeff_converter
     
     cx, cy = coeff_converter.sip2idc(wcsobj)
+    # cx, cy can be None because either there is no model available 
+    # or updatewcs was not run.
+    if cx == None or cy == None:
+        if foundIDCTAB(wcsobj.idctab):
+            m = """IDCTAB is present but distortion model is missing.
+            Run updatewcs() to update the headers or 
+            pass 'undistort=False' keyword to output_wcs().\n
+            """
+            raise RuntimeError, m
+        else:
+            print 'Distortion model is not available, using input reference image for output WCS.\n'
+            return wcsobj.copy()
     crpix1 = wcsobj.wcs.crpix[0]
     crpix2 = wcsobj.wcs.crpix[1]
     xy = np.array([(crpix1,crpix2),(crpix1+1.,crpix2),(crpix1,crpix2+1.)],dtype=np.double)
@@ -75,8 +89,8 @@ def  undistortWCS(wcsobj):
     if ( _det == 0.0):
         print 'Singular matrix in updateWCS, aborting ...'
         return
-    #lin_wcsobj = wcsutil.HSTWCS(instrument=wcsobj.instrument)
-    lin_wcsobj = pywcs.WCS()    #instrument=wcsobj.instrument)
+    
+    lin_wcsobj = pywcs.WCS()    
     cd_inv = np.linalg.inv(cd_mat)
     lin_wcsobj.wcs.cd = np.dot(wcsobj.wcs.cd, cd_inv)
     
@@ -120,4 +134,17 @@ def apply_idc(pixpos, cx, cy, pixref, pscale= None, order=None):
 
     return  c
 
+def foundIDCTAB(idctab):
+    idctab_found = True
+    try:
+        idctab = fileutil.osfn(idctab)
+        if idctab == 'N/A' or idctab == "": 
+            idctab_found = False
+        if os.path.exists(idctab):
+            idctab_found = True
+        else:
+            idctab_found = False
+    except KeyError:
+        idctab_found = False
+    return idctab_found
 
diff --git a/updatewcs/__init__.py b/updatewcs/__init__.py
index 26834db..282d6c9 100644
--- a/updatewcs/__init__.py
+++ b/updatewcs/__init__.py
@@ -16,7 +16,7 @@ __docformat__ = 'restructuredtext'
 
 __version__ = '0.4'
 
-def updatewcs(input, vacorr=True, tddcorr=True, dgeocorr=True, checkfiles=True, d2imcorr=True):
+def updatewcs(input, vacorr=True, tddcorr=True, dgeocorr=True, d2imcorr=True, checkfiles=True):
     """
     Purpose
     =======
@@ -46,6 +46,10 @@ def updatewcs(input, vacorr=True, tddcorr=True, dgeocorr=True, checkfiles=True,
               If True, vecocity aberration correction will be applied
     `tddcorr`: boolean
               If True, time dependent distortion correction will be applied 
+    `dgeocorr`: boolean
+              If True, a Lookup table distortion will be applied
+    `d2imcorr`: boolean
+              If True, detector to image correction will be applied
     `checkfiles`: boolean
               If True, the format of the input files will be checked,
               geis and waiver fits files will be converted to MEF format.
diff --git a/wcsutil/__init__.py b/wcsutil/__init__.py
index dcce32f..791f3aa 100644
--- a/wcsutil/__init__.py
+++ b/wcsutil/__init__.py
@@ -181,25 +181,33 @@ class HSTWCS(WCS):
 
 
     def readModel(self, update=False, header=None):
+        """
+        Reads distortion model from IDCTAB.
+        If IDCTAB is not found ('N/A', "", or not found on disk), then
+        if SIP coefficients and first order IDCTAb coefficients are present
+        in the header, restore the idcmodel from the header.
+        If not - assign None to self.idcmodel.
+        """
 
-        if self.idctab == None:
+        if self.idctab == None or self.idctab == ' ':
             #Keyword idctab is not present in header - check for sip coefficients
             if header.has_key('IDCSCALE'):
-                self.readModelFromHeader(header)
+                self._readModelFromHeader(header)
             else:
-                print 'Distortion model is not available\n'
-                return
+                print "Distortion model is not available: IDCTAB=None\n"
+                self.idcmodel = None
         elif not os.path.exists(fileutil.osfn(self.idctab)):
             if header.has_key('IDCSCALE'):
-                self.readModelFromHeader(header)
+                self._readModelFromHeader(header)
             else:
-                print 'Distortion model is not available\n'
-                return
+                print 'Distortion model is not available: IDCTAB file %s not found\n' % self.idctab
+                self.idcmodel = None
         else:
-            self.readModelFromIDCTAB(header=header, update=update)
+            self._readModelFromIDCTAB(header=header, update=update)
             
-    def readModelFromHeader(self, header):
+    def _readModelFromHeader(self, header):
         # Recreate idc model from SIP coefficients and header kw
+        print 'Restoring IDC model from SIP coefficients\n'
         model = models.GeometryModel()
         cx, cy = coeff_converter.sip2idc(self)
         model.cx = cx
@@ -219,7 +227,7 @@ class HSTWCS(WCS):
         self.idcmodel = model
         
         
-    def readModelFromIDCTAB(self, header=None, update=False):
+    def _readModelFromIDCTAB(self, header=None, update=False):
         """
         Purpose
         =======
@@ -245,9 +253,8 @@ class HSTWCS(WCS):
         if update:
             if header==None:
                 print 'Update header with IDC model kw requested but header was not provided\n.'
-                return
             else:
-                self.updatehdr(header)
+                self._updatehdr(header)
     
     
     def restore(self, header=None):
@@ -281,7 +288,7 @@ class HSTWCS(WCS):
         self.setPscale()
         self.setOrient()
 
-    def updatehdr(self, ext_hdr, newkeywords=None):
+    def _updatehdr(self, ext_hdr):
         #kw2add : OCX10, OCX11, OCY10, OCY11
         # record the model in the header for use by pydrizzle
         ext_hdr.update('OCX10', self.idcmodel.cx[1,0])