After helping with the Urban Observatory exhibit at the User Conference, 2013 we were inspired to bring the same concept to mobile devices. This would provide for the same visualization and comparison of different themes across different cities around the world.
The Urban Observatory works in a grid format. All the cities to be compared would be in the bottom most row. Each had the same theme such as housing density, traffic etc,. and the map scale in each device was synchronized. As devices are stacked horizontally they would load a user defined city with the same theme and the same map scale as adjoining iPads. Likewise, vertically stacked devices would display the same city but with a different theme as defined in that row.
We replicated this concept by using multiple iPads. As soon as we put down a new iPad they would realize their position with respect to the previous iPad and would pull in the correct data. All the devices synchronized the map scale and only the same city iPads synchronized the map extent. You can change the city on one device and all the other ones would update accordingly to show a different city. We also brought in the concept of using the iPhone as a remote control to manage the themes and the cities on all the iPads. The top row of iPads could also serve additional information about the cities. We had them show the fly by video of each city shown in the iPad below.
Technical Details :
This application was written using ArcGIS Runtime SDK for iOS.
All the transactions happened using the Gamekit framework for iOS. This helped us automatically setup a sessionID to which other iPads would connect to. Using CoreLocation, we also knew their relative positions and we could connect a lot of these devices together and they automatically knew what data to pull from ArcGIS Online. They established a peer to peer networking using the bluetooth or the internet when available.
The original content for the Urban Observatory, its goals, objectives, sponsors and contributors, could be accessed at http://www.urbanobservatory.org.