1. How to create extra_metadata.json file

The dictionary has two primary keys, namely collection and item, which might have additional subkeys based on the definitions of pystac.Collection and pystac.Item.

Each collection in the STAC-Collection JSON file can have keywords and providers as list, and licence as a string at the top level. To incorporate additional fields into the STAC-Collection JSON file, we can append them to the extra_fields dictionary. The addition of extra_fields is possible within the Metadata section of the STAC-Collection JSON file.

To include pystac.common_metadata attributes in the STAC-Item JSON file, we can add them to the top level of each item. To incorporate additional fields into the STAC-Item JSON file, we can append them to the properties dictionary. The Metadata part of the STAC-Item JSON file allows for the inclusion of properties. It is important to mention that the extra_fields parameter can also be utilised to include more fields in the STAC-Item JSON file.