Add a distinct corrector for Roman

Author: mcara

CHANGELOG.rst

@@ -7,6 +7,12 @@ Release Notes
 .. 0.8.13 (unreleased)
    ===================
 
+0.9.0 (06-Mar-2026)
+====================
+
+- Added ``RomanWCSCorrector`` class to support Roman WCS. [#243]
+
+
 0.8.12 (08-Oct-2025)
 ====================
 

tweakwcs/__init__.py

@@ -18,7 +18,7 @@
 
 
 from .correctors import (WCSCorrector, JWSTWCSCorrector,  # noqa: F401
-                         FITSWCSCorrector,  # noqa: F401
+                         RomanWCSCorrector, FITSWCSCorrector,  # noqa: F401
                          TPWCS, JWSTgWCS, FITSWCS)  # noqa: F401
 from .matchutils import MatchCatalogs, XYXYMatch, TPMatch  # noqa: F401
 from .imalign import fit_wcs, align_wcs  # noqa: F401

tweakwcs/correctors.py

@@ -27,7 +27,12 @@
 
 __author__ = 'Mihai Cara'
 
-__all__ = ['WCSCorrector', 'JWSTWCSCorrector', 'FITSWCSCorrector']
+__all__ = [
+    'FITSWCSCorrector',
+    'JWSTWCSCorrector',
+    'RomanWCSCorrector',
+    'WCSCorrector',
+]
 
 log = logging.getLogger(__name__)
 log.setLevel(logging.DEBUG)
@@ -565,6 +570,7 @@ class JWSTWCSCorrector(WCSCorrector):
 
     """
     units = 'arcsec'
+    corrector_name = 'JWST tangent-plane linear correction. v1'
 
     def __init__(self, wcs, wcsinfo, meta=None):
         """
@@ -642,18 +648,19 @@ def __init__(self, wcs, wcsinfo, meta=None):
             self._default_tpcorr = JWSTWCSCorrector._tpcorr_init(
                 v2_ref=v2_ref / 3600.0,
                 v3_ref=v3_ref / 3600.0,
-                roll_ref=roll_ref
+                roll_ref=roll_ref,
+                corrector_name=self.corrector_name
             )
             self._partial_tpcorr = JWSTWCSCorrector._v2v3_to_tpcorr_from_full(
                 self._default_tpcorr
             )
 
         self._update_transformations()
 
-    @staticmethod
-    def _check_tpcorr_structure(tpcorr):
+    @classmethod
+    def _check_tpcorr_structure(cls, tpcorr):
         # implement a more sophisticated check later
-        if tpcorr.name != 'JWST tangent-plane linear correction. v1':
+        if tpcorr.name != cls.corrector_name:
             return False
         return True
 
@@ -694,7 +701,7 @@ def _tpcorr_combine_affines(tpcorr, matrix, shift):
         tpcorr.inverse['tp_affine_inv'].translation = -np.dot(invm, t)
 
     @staticmethod
-    def _tpcorr_init(v2_ref, v3_ref, roll_ref):
+    def _tpcorr_init(v2_ref, v3_ref, roll_ref, corrector_name="Unnamed"):
         s2c = SphericalToCartesian(name='s2c', wrap_lon_at=180)
         c2s = CartesianToSpherical(name='c2s', wrap_lon_at=180)
 
@@ -730,13 +737,13 @@ def _tpcorr_init(v2_ref, v3_ref, roll_ref):
             unit_conv | s2c | rot | c2tan | affine |
             tan2c | rot_inv | c2s | unit_conv_inv
         )
-        total_corr.name = 'JWST tangent-plane linear correction. v1'
+        total_corr.name = corrector_name
 
         inv_total_corr = (
             unit_conv | s2c | rot | c2tan | affine_inv |
             tan2c | rot_inv | c2s | unit_conv_inv
         )
-        inv_total_corr.name = 'Inverse JWST tangent-plane linear correction. v1'
+        inv_total_corr.name = f'Inverse {corrector_name}'
 
         # TODO
         # re-enable circular inverse definitions once
@@ -859,7 +866,8 @@ def set_correction(self, matrix=[[1, 0], [0, 1]], shift=[0, 0],
             self._tpcorr = JWSTWCSCorrector._tpcorr_init(
                 v2_ref=self._wcsinfo['v2_ref'] / 3600.0,
                 v3_ref=self._wcsinfo['v3_ref'] / 3600.0,
-                roll_ref=self._wcsinfo['roll_ref']
+                roll_ref=self._wcsinfo['roll_ref'],
+                corrector_name=self.corrector_name
             )
 
             JWSTWCSCorrector._tpcorr_combine_affines(
@@ -1043,6 +1051,17 @@ def bounding_box(self):
             return self._owcs.pixel_bounds
 
 
+class RomanWCSCorrector(JWSTWCSCorrector):
+    """ A class for holding ``Roman`` ``GWCS`` information and for managing
+    tangent-plane corrections. The units of the tangent plane of this
+    corrector are ``arcsec`` and the axes are not along parallel to the
+    axes of the detector's coordinate system.
+
+    """
+    units = 'arcsec'
+    corrector_name = 'Roman tangent-plane linear correction. v1'
+
+
 @deprecated(since='0.8.0', alternative='WCSCorrector')
 class TPWCS(WCSCorrector):
     pass

tweakwcs/tests/test_multichip_jwst.py

@@ -1,3 +1,5 @@
+import pytest
+
 import numpy as np
 from astropy.io import fits
 from astropy import table
@@ -125,10 +127,11 @@ def _match(x, y, tp_pscale, tp_units, **kwargs):
     return match
 
 
-def test_multichip_jwst_alignment():
+@pytest.mark.parametrize('corrector_cls', ['JWSTWCSCorrector', 'RomanWCSCorrector'])
+def test_multichip_jwst_alignment(corrector_cls):
     w1 = _make_gwcs_wcs('data/wfc3_uvis1.hdr')
 
-    imcat1 = tweakwcs.JWSTWCSCorrector(w1, {'v2_ref': 0, 'v3_ref': 0, 'roll_ref': 0})
+    imcat1 = getattr(tweakwcs, corrector_cls)(w1, {'v2_ref': 0, 'v3_ref': 0, 'roll_ref': 0})
     imcat1.meta['catalog'] = table.Table.read(
         get_pkg_data_filename('data/wfc3_uvis1.cat'),
         format='ascii.csv',
@@ -141,7 +144,7 @@ def test_multichip_jwst_alignment():
     imcat1.meta['name'] = 'ext1'
 
     w2 = _make_gwcs_wcs('data/wfc3_uvis2.hdr')
-    imcat2 = tweakwcs.JWSTWCSCorrector(w2, {'v2_ref': 0, 'v3_ref': 0, 'roll_ref': 0})
+    imcat2 = getattr(tweakwcs, corrector_cls)(w2, {'v2_ref': 0, 'v3_ref': 0, 'roll_ref': 0})
     imcat2.meta['catalog'] = table.Table.read(
         get_pkg_data_filename('data/wfc3_uvis2.cat'),
         format='ascii.csv',