JP-4275: Store mosaic members' WCS objects along with some metadata in ImageModels

src/stdatamodels/fits_support.py

@@ -11,6 +11,7 @@
 import numpy as np
 from asdf import schema as asdf_schema
 from asdf import tagged, treeutil
+from asdf.exceptions import ValidationError
 from asdf.tags.core import HistoryEntry, NDArrayType, ndarray
 from asdf.util import HashableDict
 from astropy import time
@@ -375,6 +376,17 @@ def _get_validators(hdulist):
     fits_context = FitsContext(hdulist)
 
     validators = HashableDict(asdf_schema.YAML_VALIDATORS)
+    tag_validator = validators["tag"]
+
+    def validate_tag(validator, tag_pattern, instance, schema):
+        af = asdf.AsdfFile()
+        if af.extension_manager.handles_type(instance.__class__):
+            for tag in af.extension_manager.get_converter_for_type(instance.__class__).tags:
+                tag_validator(validator, tag_pattern, tag, schema)
+            return
+        raise ValidationError(
+            f"Unsupported {instance} does not have a tag matching pattern {tag_pattern}"
+        )
 
     partial_fits_array_writer = partial(_fits_array_writer, fits_context)
 
@@ -387,6 +399,7 @@ def _get_validators(hdulist):
             "items": partial(_fits_item_recurse, fits_context),
             "properties": partial(_fits_comment_section_handler, fits_context),
             "type": partial(_fits_type, fits_context),
+            "tag": validate_tag,
         }
     )
 

src/stdatamodels/jwst/datamodels/__init__.py

@@ -41,6 +41,7 @@
 from .level1b import Level1bModel
 from .linearity import LinearityModel
 from .mask import MaskModel
+from .member_wcs import MemberWcsModel, MemberWcsSingleModel
 from .model_base import JwstDataModel
 from .mrsptcorr import MirMrsPtCorrModel
 from .mrsxartcorr import MirMrsXArtCorrModel
@@ -180,6 +181,8 @@
     "MRSSpecModel",
     "MSAModel",
     "MaskModel",
+    "MemberWcsModel",
+    "MemberWcsSingleModel",
     "MirImgApcorrModel",
     "MirImgPhotomModel",
     "MirLrsApcorrModel",

src/stdatamodels/jwst/datamodels/member_wcs.py

@@ -0,0 +1,52 @@
+__all__ = ["MemberWcsModel", "MemberWcsSingleModel"]
+
+
+class MemberWcsModel:
+    """
+    A data model for storing WCS objects from a list of image models.
+
+    This model is meant to store all WCS objects from input images used to generate
+    a mosaic during image resampling.  It behaves like a list::
+
+       >>> from stdatamodels.jwst.datamodels import MemberWcsModel
+       >>> memberwcs_model = MemberWcsModel()
+       >>> memberwcs_model.member_wcs.append(MemberWcsSingleModel())
+       >>> memberwcs_model.member_wcs[0] # doctest: +SKIP
+       <MemberWcsSingleModel>
+
+    If `init` is a `MemberWcsSingleModel` instance, an empty `MemberWcsSingleModel`
+    will be created and assigned to attribute `member_wcs[0]`.
+    `SpecProfileSingleModel` objects can be appended to the `member_wcs` attribute
+    by using its `append` method.
+
+    Attributes
+    ----------
+    member_wcs : list
+         List of ~`stdatamodels.jwst.datamodels.MemberWcsSingleModel` objects.
+    """
+
+    schema_url = "http://stsci.edu/schemas/jwst_datamodel/member_wcs.schema"
+
+    def __init__(self, init=None):
+        self.member_wcs = []
+        if isinstance(init, MemberWcsSingleModel):
+            self.member_wcs.append(init)
+
+
+class MemberWcsSingleModel:
+    """
+    A simple data model to store a filename and associated imaging WCS object.
+
+    Attributes
+    ----------
+    filename : string
+         The mosaic member filename.
+    wcs : ~`gwcs.wcs.WCS` object
+        The member's image WCS object.
+    """
+
+    schema_url = "http://stsci.edu/schemas/jwst_datamodel/member_wcs_single.schema"
+
+    def __init__(self, filename=None, wcs=None):
+        self.filename = filename
+        self.wcs = wcs

src/stdatamodels/jwst/datamodels/schemas/image.schema.yaml

@@ -57,5 +57,23 @@ allOf:
       default: 0
       ndim: 2
       datatype: uint32
+    member_wcs:
+      type: array
+      title: List of mosaic member WCS objects
+      items:
+        type: object
+        properties:
+          filename:
+            title: Member filename
+            type: string
+          ra_ref:
+            title: Member reference RA
+            type: number
+          dec_ref:
+            title: Member reference Dec
+            type: number
+          wcs:
+            title: Member WCS
+            tag: tag:stsci.edu:gwcs/wcs-*
 - $ref: variance.schema
 - $ref: pathlosscorr.schema