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| author | hack <hack@stsci.edu> | 2011-03-18 15:07:21 -0400 |
|---|---|---|
| committer | hack <hack@stsci.edu> | 2011-03-18 15:07:21 -0400 |
| commit | c006f69626bf5ada3af158504362926d60b3e297 (patch) | |
| tree | eef08106de370812b9bb3480cf2797d7527ec12c /distortion/utils.py | |
| parent | 3262a4afa935fdd89e40f30e0a254cf0b6eeaf8e (diff) | |
| download | stwcs_hcf-c006f69626bf5ada3af158504362926d60b3e297.tar.gz | |
Revised how 'output_wcs' computes the new WCS, specifically, correctly accounting for the fact that the center computed on the sky is a zero-based computation, not a 1-based computation as assumed before. This eliminates the 1 pixel offset introduced when creating an output WCS with an input WCS which has no distortion model.
git-svn-id: http://svn.stsci.edu/svn/ssb/stsci_python/stsci_python/trunk/stwcs@12260 fe389314-cf27-0410-b35b-8c050e845b92
Diffstat (limited to 'distortion/utils.py')
| -rw-r--r-- | distortion/utils.py | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/distortion/utils.py b/distortion/utils.py index ad58f95..a99e227 100644 --- a/distortion/utils.py +++ b/distortion/utils.py @@ -30,7 +30,7 @@ def output_wcs(list_of_wcsobj, ref_wcs=None, owcs=None, undistort=True): # robust in handling regions near the poles or at 0h RA. crval1,crval2 = computeFootprintCenter(fra_dec) - crval = np.array([crval1,crval2], dtype=np.float64) + crval = np.array([crval1,crval2], dtype=np.float64) # this value is now zero-based if owcs is None: if ref_wcs == None: ref_wcs = list_of_wcsobj[0].deepcopy() @@ -46,20 +46,21 @@ def output_wcs(list_of_wcsobj, ref_wcs=None, owcs=None, undistort=True): outwcs = owcs.deepcopy() outwcs.pscale = sqrt(outwcs.wcs.cd[0,0]**2 + outwcs.wcs.cd[1,0]**2)*3600. outwcs.orientat = arctan2(outwcs.wcs.cd[0,1],outwcs.wcs.cd[1,1]) * 180./np.pi - - tanpix = outwcs.wcs.s2p(fra_dec, 1)['pixcrd'] - + + tanpix = outwcs.wcs.s2p(fra_dec, 0)['pixcrd'] + outwcs.naxis1 = int(np.ceil(tanpix[:,0].max() - tanpix[:,0].min())) outwcs.naxis2 = int(np.ceil(tanpix[:,1].max() - tanpix[:,1].min())) crpix = np.array([outwcs.naxis1/2., outwcs.naxis2/2.], dtype=np.float64) outwcs.wcs.crpix = crpix outwcs.wcs.set() - tanpix = outwcs.wcs.s2p(fra_dec, 1)['pixcrd'] + tanpix = outwcs.wcs.s2p(fra_dec, 0)['pixcrd'] # shift crpix to take into account (floating-point value of) position of # corner pixel relative to output frame size: no rounding necessary... newcrpix = np.array([crpix[0]+tanpix[:,0].min(), crpix[1]+ tanpix[:,1].min()]) + newcrval = outwcs.wcs.p2s([newcrpix], 1)['world'][0] outwcs.wcs.crval = newcrval outwcs.wcs.set() |