This disclosure provides a federated wide area motion imagery (WAMI) collection service (CS) by: receiving an alert from a WAMI alert-service (A) respectively associated with a WAMI CS regarding any updates to WAMI data served by the WAMI CS at the federated WAMI CS, the WAMI CS providing WAMI collection metadata; issuing a request to the WAMI A associated with the WAMI CS to read information on what is updated; receiving a response from the WAMI A at the federated WAMI CS, the response comprising tree nodes corresponding to WAMI collection metadata that are updated by the WAMI CS; issuing a subsequent request to the WAMI CS from the federated WAMI CS to retrieve the WAMI collection metadata from the WAMI CS corresponding to the collection tree nodes that are updated; receiving a response including the WAMI collection metadata from the WAMI CS; and storing the received WAMI collection metadata in cache of the federated WAMI CS of the system.