Connect to a Stream Layer
Poll information thru a web socket on a stream layer to update information in real time.
How it works
Getting the data
In this sample a websocket is used to subscribe to a Stream Server. This Stream Server returns information from flights over the United States including location and flight callsign to update Game Objects in real time. This service ws://geoeventsample1.esri.com:6180/arcgis/ws/services/FAAStream/StreamServer/subscribe in the sample is actually mocked information so it is not accurate in real time but using a service with real time information the workflow would be the same.
Making the connection
To make the connection we just use Unity's ClientWebSocket class. We open the connection with the desired URL and while the connection remains open we process the result.
Parsing the response
Every time the StreamServer has an update for a new plane or an existing one we are showing we need to parse the JSON response. [System.Serializable] classes are made to leverage Unity's built in JSON parsing. We grab the location, speed, heading, time the update was sent and the plane name. All of this information is used to display the plane in the correct location as well as inputs for a DeadReckoning system that updates each planes location every frame so that the plane has a smooth animation instead of jumping from place to place every time we receive a new signal.
How to Use
These new game objects are then used to populate the drop-down list allowing you to quickly navigate to other planes by updating the ArcGIS Camera location. When flying around the scene you may encounter a plane especially if you are near a large airport.
About the data
This sample uses the geoevent stream server plane location stream layer. This data was recorded in the past and played back in real time. It is not a live update of current air traffic.
Tags
steam, stream layer, stream service, websocket, planes