Create an AERONET Item¶

Install the package, then run this complete example. The station, coordinates, reporting interval, and availability counts are synthetic; they are not NASA observations.

import json
from datetime import datetime, timezone

import pystac
from pystac.extensions.aeronet import AeronetExtension

item = pystac.Item(
    id="example-aeronet-station",
    geometry={"type": "Point", "coordinates": [12.5, 41.9]},
    bbox=[12.5, 41.9, 12.5, 41.9],
    datetime=None,
    start_datetime=datetime(2026, 1, 1, tzinfo=timezone.utc),
    end_datetime=datetime(2026, 1, 31, 23, 59, 59, tzinfo=timezone.utc),
    properties={"title": "Synthetic AERONET station"},
)
aeronet = AeronetExtension.ext(item, add_if_missing=True)
aeronet.apply(
    site_name="Example_Station",
    land_use_type="Urban",
    L10=25,
    L15=20,
    L20=18,
    moon_L15=0,
)

serialized = item.to_dict()
assert AeronetExtension.get_schema_uri() in serialized["stac_extensions"]
assert serialized["properties"]["aeronet:L20"] == 18

restored_item = pystac.Item.from_dict(json.loads(json.dumps(serialized)))
restored = AeronetExtension.from_item(restored_item)
assert restored.site_name == "Example_Station"
assert restored.L20 == 18
assert restored.moon_L15 == 0

add_if_missing=True adds the schema URL to item.stac_extensions. apply() requires all six arguments and writes them directly into item.properties. The four integer fields describe days of data availability; zero is a valid stored value.

This example uses an Item interval to describe its reporting period. The wrapper neither chooses the Item's temporal extent nor derives counts from it. Supply a period and counts appropriate to your source data.

Serialization preserves the metadata but does not validate it against JSON Schema. Continue with updates and validation.