RCAL-919: Formalize the patches (sky cells) file (e.g., add a data mo…

…del to support it as a reference fiel) (#441)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Nadia Dencheva <[email protected]>

changes/441.feature.rst

@@ -0,0 +1 @@
+Added support for skycell reference file

pyproject.toml

@@ -19,7 +19,6 @@ dependencies = [
     "gwcs >=0.19.0",
     "numpy >=1.24",
     "astropy >=5.3.0",
-    # "rad >=0.23.0, <0.24.0",
     "rad @ git+https://github.com/spacetelescope/rad.git",
     "asdf-standard >=1.1.0",
 ]

src/roman_datamodels/datamodels/_datamodels.py

@@ -302,6 +302,10 @@ class ReadnoiseRefModel(_DataModel):
     _node_type = stnode.ReadnoiseRef
 
 
+class SkycellsRefModel(_DataModel):
+    _node_type = stnode.SkycellsRef
+
+
 class SuperbiasRefModel(_DataModel):
     _node_type = stnode.SuperbiasRef
 

src/roman_datamodels/maker_utils/_common_meta.py

@@ -748,6 +748,25 @@ def mk_ref_readnoise_meta(**kwargs):
     return meta
 
 
+def mk_ref_skycells_meta(**kwargs):
+    """
+    Create dummy metadata for skycells reference file instances.
+
+    Returns
+    -------
+    dict (follows reference_file/ref_common-1.0.0 schema + skycell reference file meta data)
+    """
+    meta = mk_ref_common("SKYCELLS", **kwargs)
+    if "instrument" in meta:
+        meta["instrument"].pop("detector", None)
+        meta["instrument"].pop("optical_element", None)
+    meta["nxy_skycell"] = kwargs.get("nxy_skycell", 5000)
+    meta["skycell_border_pixels"] = kwargs.get("skycell_border_pixels", 100)
+    meta["plate_scale"] = kwargs.get("plate_scale", 0.055)
+
+    return meta
+
+
 def mk_mosaic_basic(**kwargs):
     """
     Create a dummy mosaic basic instance with valid values for attributes

src/roman_datamodels/maker_utils/_ref_files.py

@@ -13,6 +13,7 @@
     mk_ref_epsf_meta,
     mk_ref_pixelarea_meta,
     mk_ref_readnoise_meta,
+    mk_ref_skycells_meta,
     mk_ref_units_dn_meta,
 )
 
@@ -32,6 +33,7 @@
     "mk_readnoise",
     "mk_refpix",
     "mk_saturation",
+    "mk_skycells",
     "mk_superbias",
     "mk_wfi_img_photom",
 ]
@@ -560,6 +562,54 @@ def mk_saturation(*, shape=(4096, 4096), filepath=None, **kwargs):
     return save_node(saturationref, filepath=filepath)
 
 
+def mk_skycells(*, shape_pr=(100,), shape_sc=(1000,), filepath=None, **kwargs):
+    skycellref = stnode.SkycellsRef()
+    skycellref["meta"] = mk_ref_skycells_meta(**kwargs.get("meta", {}))
+    proj_dtype = np.dtype(
+        [
+            ("index", "<i4"),
+            ("ra_tangent", "<f8"),
+            ("dec_tangent", "<f8"),
+            ("ra_min", "<f8"),
+            ("ra_max", "<f8"),
+            ("dec_min", "<f8"),
+            ("dec_max", "<f8"),
+            ("orientat", "<f4"),
+            ("x_tangent", "<f8"),
+            ("y_tangent", "<f8"),
+            ("nx", "<i4"),
+            ("ny", "<i4"),
+            ("skycell_start", "<i4"),
+            ("skycell_end", "<i4"),
+        ]
+    )
+    skycell_dtype = np.dtype(
+        [
+            ("name", "<U16"),
+            ("ra_center", "<f8"),
+            ("dec_center", "<f8"),
+            ("orientat", "<f4"),
+            ("x_tangent", "<f8"),
+            ("y_tangent", "<f8"),
+            ("ra_corn1", "<f8"),
+            ("dec_corn1", "<f8"),
+            ("ra_corn2", "<f8"),
+            ("dec_corn2", "<f8"),
+            ("ra_corn3", "<f8"),
+            ("dec_corn3", "<f8"),
+            ("ra_corn4", "<f8"),
+            ("dec_corn4", "<f8"),
+        ]
+    )
+    proj_tab = kwargs.get("projection_regions", np.zeros(shape_pr, dtype=proj_dtype))
+    proj_tab[:]["index"] = np.arange(len(proj_tab))
+    skycell_tab = kwargs.get("skycells", np.zeros(shape_sc, dtype=skycell_dtype))
+    skycellref["projection_regions"] = proj_tab
+    skycellref["skycells"] = skycell_tab
+
+    return save_node(skycellref, filepath=filepath)
+
+
 def mk_superbias(*, shape=(4096, 4096), filepath=None, **kwargs):
     """
     Create a dummy Superbias instance (or file) with arrays and valid values for

tests/test_models.py

@@ -583,6 +583,12 @@ def test_make_refpix():
     assert refpix.alpha.shape == (8, 8)
 
 
+# Skycells tests
+def test_make_skycells():
+    skycells_ref = utils.mk_skycells()
+    assert skycells_ref.projection_regions["index"][2] == 2
+
+
 # WFI Photom tests
 def test_make_wfi_img_photom():
     wfi_img_photom = utils.mk_wfi_img_photom()

tests/test_open.py

@@ -227,7 +227,11 @@ def test_opening_model(tmp_path, node_class):
         elif node_class in (stnode.MosaicSegmentationMap, stnode.MosaicSourceCatalog):
             assert hasattr(model.meta, "basic")
         else:
-            assert model.meta.instrument.optical_element == "F158"
+            # roman_skycells reference file does not contain optical_element. Skip this case
+            if hasattr(model.meta, "reftype") and model.meta.reftype == "SKYCELLS":
+                pass
+            else:
+                assert model.meta.instrument.optical_element == "F158"
 
         # Check that the model is the correct type
         assert isinstance(model, datamodels.MODEL_REGISTRY[node_class])