Theme fields¶

The extension uses the unprefixed JSON field themes. Each entry groups concepts from one scheme. The package declares the Themes v1.0.0 schema.

JSON field	Python attribute	Python type	Meaning
themes	ThemesExtension.themes	list[Theme] \| None	The object's thematic classifications.
scheme	Theme.scheme	str	URI identifying the vocabulary or knowledge organization system.
concepts	Theme.concepts	list[ThemeConcept]	Concepts selected from that scheme.
id	ThemeConcept.id	str	Identifier of a concept within the scheme.
title	ThemeConcept.title	str \| None	Optional human-readable title.
description	ThemeConcept.description	str \| None	Optional description of the concept.
url	ThemeConcept.url	str \| None	Optional link describing the concept.

ThemeConcept.to_dict() omits optional values set to None. Theme.from_dict() and ThemeConcept.from_dict() require their mandatory keys; they do not perform schema validation or preserve unrecognized fields.

Storage¶

Items store themes inside properties. Catalogs and Collections store it at the top level through extra_fields. ThemesExtension.summaries(collection) separately accesses collection.summaries["themes"].

A missing or JSON-null theme field reads as None. Assigning None removes the field; assigning [] stores an empty list. These storage behaviors do not establish schema validity.

Getters deserialize new Python objects. After changing a returned theme or concept, assign the list back to the wrapper to persist the edit. Assignments serialize values immediately and preserve unrelated STAC properties.