Scope, architecture, and validation¶

Package structure¶

The distribution is named pystac-ext-insar, while the import path is pystac.extensions.insar. The wheel excludes the shared pystac.extensions initializer owned by PySTAC.

InsarExtension.ext() selects a wrapper for an Item, Asset, or ItemAssetDefinition. These wrappers write directly into the wrapped object's dictionaries, so serialization uses PySTAC's normal to_dict() method. The package stores metadata; it does not generate interferograms, calculate baselines, or retrieve DEMs.

Asset wrappers use only the asset's extra fields and do not fall back to Item properties. Extension membership for assets and item asset definitions is managed through their owner.

Collection summaries¶

Collections use InsarExtension.summaries(). The current helper supports reference datetime and the two DEM properties as single-element lists. It does not compute summaries from Items. Reading a multi-element list returns only the first value; writing through the helper replaces the list. Use PySTAC's Collection summary APIs directly when you need other summary shapes or fields.

Validation boundaries¶

Numeric setters reject booleans and nonnumeric values. DEM setters check string types. They do not validate numeric ranges, DEM availability, or relationships among acquisition dates and baselines. Type annotations guide callers but do not enforce every constraint at runtime. Reading an existing document does not revalidate its properties through the setters.

apply() mutates fields sequentially. If a later setter fails, earlier assignments remain. It also clears fields whose values are omitted. Validate inputs first if your application requires an all-or-nothing update.

For full STAC and extension validation, install PySTAC's validation extra with python -m pip install "pystac[validation]" and call item.validate(). Validation may retrieve remote schemas, so the referenced schema URLs must be accessible or supplied through an application-configured validator. Neither apply() nor to_dict() performs JSON Schema validation.

The field reference describes the current wrapper's checks and supported summaries.

Migration hooks¶

INSAR_EXTENSION_HOOKS declares the schema identifier, the legacy identifier insar, and Item/Collection object types. The module exposes this hook object but does not automatically register it with PySTAC.