Sync wcs

CHANGES.rst

@@ -28,6 +28,12 @@ Other Changes and Additions
 
 - Added support for .bz2, .Z and .zip file formats in ``ImageFileCollection``.
 
+- Added warning that ``transform_image`` does not apply the transformation to
+  the WCS [#684]
+
+- When creating a new object in ``wcs_transform``, WCS keywords in the header
+  are removed so that they are only stored in the WCS object [#685]
+
 - Removed support for initializing ``ImageFileCollection`` from a table instead
   of files. [#680]
 

ccdproc/core.py

@@ -2,10 +2,13 @@
 
 """This module implements the base CCDPROC functions"""
 
+import math
 import numbers
+import logging
 
 import numpy as np
-import math
+from scipy import ndimage
+
 from astropy.units.quantity import Quantity
 from astropy import units as u
 from astropy.modeling import fitting
@@ -16,12 +19,12 @@
 from astropy.utils import deprecated
 import astropy  # To get the version.
 
-from scipy import ndimage
-
 from .utils.slices import slice_from_string
 from .log_meta import log_to_metadata
 from .extern.bitfield import bitfield_to_boolean_mask as _bitfield_to_boolean_mask
 
+logger = logging.getLogger(__name__)
+
 __all__ = ['background_deviation_box', 'background_deviation_filter',
            'ccd_process', 'cosmicray_median', 'cosmicray_lacosmic',
            'create_deviation', 'flat_correct', 'gain_correct', 'rebin',
@@ -853,6 +856,10 @@ def transform_image(ccd, transform_func, **kwargs):
         mask = transform_func(nccd.mask, **kwargs)
         nccd.mask = mask > 0
 
+    if nccd.wcs is not None:
+        warn = 'WCS information may be incorrect as no transformation was applied to it'
+        logging.warning(warn)
+
     return nccd
 
 
@@ -895,6 +902,7 @@ def wcs_project(ccd, target_wcs, target_shape=None, order='bilinear'):
     ccd : `~astropy.nddata.CCDData`
         A transformed CCDData object.
     """
+    from astropy.nddata.ccddata import _generate_wcs_and_update_header
     from reproject import reproject_interp
 
     if not (ccd.wcs.is_celestial and target_wcs.is_celestial):
@@ -934,9 +942,12 @@ def wcs_project(ccd, target_wcs, target_shape=None, order='bilinear'):
     if not output_mask.any():
         output_mask = None
 
+    # If there are any wcs keywords in the header, remove them
+    hdr, _ = _generate_wcs_and_update_header(ccd.header)
+
     nccd = CCDData(area_ratio * projected_image_raw, wcs=target_wcs,
                    mask=output_mask,
-                   header=ccd.header, unit=ccd.unit)
+                   header=hdr, unit=ccd.unit)
 
     return nccd
 

ccdproc/tests/test_ccdproc.py

@@ -432,6 +432,7 @@ def test_unit_mismatch_behaves_as_expected(ccd_data):
     # Was the error message as expected?
     assert expected_message in str(e.value)
 
+
 # test for flat correction
 @pytest.mark.data_scale(10)
 def test_flat_correct(ccd_data):
@@ -443,7 +444,7 @@ def test_flat_correct(ccd_data):
     flat = CCDData(data, meta=fits.header.Header(), unit=ccd_data.unit)
     flat_data = flat_correct(ccd_data, flat, add_keyword=None)
 
-    #check that the flat was normalized
+    # check that the flat was normalized
     # Should be the case that flat * flat_data = ccd_data * flat.data.mean
     # if the normalization was done correctly.
     np.testing.assert_almost_equal((flat_data.data * flat.data).mean(),
@@ -545,6 +546,7 @@ def test_flat_correct_data_uncertainty():
     assert (res.data == dat.data).all()
     assert (res.uncertainty.array == dat.uncertainty.array).all()
 
+
 # tests for gain correction
 def test_gain_correct(ccd_data):
     init_data = ccd_data.data
@@ -562,18 +564,28 @@ def test_gain_correct_quantity(ccd_data):
     assert ccd_data.unit == u.electron
 
 
-#test transform is ccd
+# test transform is ccd
 def test_transform_isccd():
     with pytest.raises(TypeError):
         transform_image(1, 1)
 
 
-#test function is callable
+# test function is callable
 def test_transform_isfunc(ccd_data):
     with pytest.raises(TypeError):
         transform_image(ccd_data, 1)
 
 
+# test warning is issue if WCS information is available
+def test_catch_transform_wcs_warning(ccd_data):
+
+    def tran(arr):
+        return 10 * arr
+
+    with catch_warnings() as w:
+        tran = transform_image(ccd_data, tran)
+
+
 @pytest.mark.parametrize('mask_data, uncertainty', [
                          (False, False),
                          (True, True)])
@@ -691,20 +703,20 @@ def test_block_replicate():
     assert 'testkw2' not in ccd.meta
 
 
-#test blockaveraging ndarray
+# test blockaveraging ndarray
 def test__blkavg_ndarray():
     with pytest.raises(TypeError):
         _blkavg(1, (5, 5))
 
 
-#test rebinning dimensions
+# test rebinning dimensions
 @pytest.mark.data_size(10)
 def test__blkavg_dimensions(ccd_data):
     with pytest.raises(ValueError):
         _blkavg(ccd_data.data, (5,))
 
 
-#test blkavg works
+# test blkavg works
 @pytest.mark.data_size(20)
 def test__blkavg_larger(ccd_data):
     a = ccd_data.data
@@ -714,10 +726,10 @@ def test__blkavg_larger(ccd_data):
     np.testing.assert_almost_equal(b.sum(), 0.25 * a.sum())
 
 
-#test overscan changes
+# test overscan changes
 def test__overscan_schange(ccd_data):
     old_data = ccd_data.copy()
-    new_data = subtract_overscan(ccd_data, overscan=ccd_data[:,1], overscan_axis=0)
+    new_data = subtract_overscan(ccd_data, overscan=ccd_data[:, 1], overscan_axis=0)
     assert not np.allclose(old_data.data, new_data.data)
     np.testing.assert_array_equal(old_data.data, ccd_data.data)
 
@@ -728,40 +740,46 @@ def test_create_deviation_does_not_change_input(ccd_data):
     np.testing.assert_array_equal(original.data, ccd_data.data)
     assert original.unit == ccd_data.unit
 
+
 def test_cosmicray_median_does_not_change_input(ccd_data):
     original = ccd_data.copy()
     error = np.zeros_like(ccd_data)
-    ccd = cosmicray_median(ccd_data,error_image=error, thresh=5, mbox=11, gbox=0, rbox=0)
-    np.testing.assert_array_equal(original.data,ccd_data.data)
+    ccd = cosmicray_median(ccd_data, error_image=error, thresh=5, mbox=11, gbox=0, rbox=0)
+    np.testing.assert_array_equal(original.data, ccd_data.data)
     assert original.unit == ccd_data.unit
 
+
 def test_cosmicray_lacosmic_does_not_change_input(ccd_data):
     original = ccd_data.copy()
     error = np.zeros_like(ccd_data)
     ccd = cosmicray_lacosmic(ccd_data)
     np.testing.assert_array_equal(original.data, ccd_data.data)
     assert original.unit == ccd_data.unit
 
+
 def test_flat_correct_does_not_change_input(ccd_data):
     original = ccd_data.copy()
     flat = CCDData(np.zeros_like(ccd_data), unit=ccd_data.unit)
-    ccd = flat_correct(ccd_data,flat=flat)
+    ccd = flat_correct(ccd_data, flat=flat)
     np.testing.assert_array_equal(original.data, ccd_data.data)
     assert original.unit == ccd_data.unit
 
+
 def test_gain_correct_does_not_change_input(ccd_data):
     original = ccd_data.copy()
     ccd = gain_correct(ccd_data, gain=1, gain_unit=ccd_data.unit)
     np.testing.assert_array_equal(original.data, ccd_data.data)
     assert original.unit == ccd_data.unit
 
+
 def test_subtract_bias_does_not_change_input(ccd_data):
     original = ccd_data.copy()
     master_frame = CCDData(np.zeros_like(ccd_data), unit=ccd_data.unit)
     ccd = subtract_bias(ccd_data, master=master_frame)
     np.testing.assert_array_equal(original.data, ccd_data.data)
     assert original.unit == ccd_data.unit
 
+
 def test_trim_image_does_not_change_input(ccd_data):
     original = ccd_data.copy()
     ccd = trim_image(ccd_data, fits_section=None)
@@ -809,6 +827,19 @@ def test_wcs_project_onto_same_wcs(ccd_data):
     np.testing.assert_allclose(ccd_data.data, new_ccd.data, rtol=1e-5)
 
 
+def test_wcs_project_onto_same_wcs_remove_headers(ccd_data):
+    # Remove an example WCS keyword from the header
+    target_wcs = wcs_for_testing(ccd_data.shape)
+    ccd_data.wcs = wcs_for_testing(ccd_data.shape)
+    print(ccd_data.header)
+    ccd_data.header = ccd_data.wcs.to_header()
+
+    new_ccd = wcs_project(ccd_data, target_wcs)
+
+    for k in ccd_data.wcs.to_header():
+        assert k not in new_ccd.header
+
+
 def test_wcs_project_onto_shifted_wcs(ccd_data):
     # Just make the target WCS the same as the initial with the center
     # pixel shifted by 1 in x and y.
@@ -974,12 +1005,13 @@ def test_ccd_process():
 
     np.testing.assert_array_equal(2.0 * np.ones((100, 90)), occd.data)
     np.testing.assert_almost_equal(3.0 * np.ones((100, 90)),
-                                  occd.uncertainty.array)
+                                   occd.uncertainty.array)
     np.testing.assert_array_equal(mask, occd.mask)
     assert(occd.unit == u.electron)
     # Make sure the original keyword is still present. Regression test for #401
     assert occd.meta['testkw'] == 100
 
+
 def test_ccd_process_gain_corrected():
     # test the through ccd_process with gain_corrected as False
     ccd_data = CCDData(10.0 * np.ones((100, 100)), unit=u.adu)
@@ -1010,7 +1042,7 @@ def test_ccd_process_gain_corrected():
 
     np.testing.assert_array_equal(2.0 * np.ones((100, 90)), occd.data)
     np.testing.assert_almost_equal(3.0 * np.ones((100, 90)),
-                                  occd.uncertainty.array)
+                                   occd.uncertainty.array)
     np.testing.assert_array_equal(mask, occd.mask)
     assert(occd.unit == u.electron)
     # Make sure the original keyword is still present. Regression test for #401