Work with AERONET metadata¶

These examples continue from the Item created in the tutorial.

Update one field¶

aeronet = AeronetExtension.ext(item)
aeronet.L20 = 19
assert item.properties["aeronet:L20"] == 19
assert aeronet.site_name == "Example_Station"

Individual setters preserve other properties. To replace all six fields, call apply() with all six arguments, as in the tutorial. There are no default values in apply().

Open an existing Item¶

AeronetExtension.from_item(item) is an alias for AeronetExtension.ext(item). Both require the extension URL to be declared, unless you pass add_if_missing=True.

if AeronetExtension.has_extension(restored_item):
    existing = AeronetExtension.from_item(restored_item)
    assert existing.site_name == "Example_Station"

Accessing a missing or JSON-null AERONET field raises pystac.RequiredPropertyMissing. Attaching the extension alone does not populate those fields. Supply all required values before publishing the Item.

Manage extension membership¶

AeronetExtension.remove_from(item)
assert not AeronetExtension.has_extension(item)
assert item.properties["aeronet:site_name"] == "Example_Station"

AeronetExtension.add_to(item)
AeronetExtension.add_to(item)
assert item.stac_extensions.count(AeronetExtension.get_schema_uri()) == 1

Removal changes the extension declaration only; stored fields remain. Assigning None is outside the setter type contract and does not remove a field. If you intentionally remove AERONET metadata, remove its properties explicitly as well as its declaration.

Validate a complete Item¶

Install PySTAC's validation dependencies:

python -m pip install "pystac[validation]>=1,<2"

Then, with all required values populated:

item.validate()

Validation may fetch STAC and extension schemas over the network. For offline use, configure a PySTAC validator with locally available schemas. apply() and to_dict() do not invoke validation. See the validation boundaries for the checks performed by this wrapper.