ReadonlyfeatureThe feature's ordinal within its node (0-based).
ReadonlyfieldsEvery per-feature attribute value, keyed by I3S field name (null for a missing value).
ReadonlyobjectBest-effort object id from an *object*id* attribute, or null if the feature has none.
A picked Point FEATURE: its objectId (best-effort, from an
*object*id*attribute), its feature ordinal within the node, and every per-feature attribute value (keyed by I3S field name). Returned by I3sPointLayer.pickFeature.