In this chapter, we will create a real-time application to explore the distribution of geotagged tweets containing user-defined topics. Creating this visualization will involve implementing a server-side application and a client-side application.

The server-side application will handle connections from the clients, receive topics to be heard on Twitter, and send tweets matching the topics to the corresponding clients.

The client-side application will connect with the streaming server, send it topics as the user enters the streaming server, receive tweets, and update the visualization as the tweets arrive.

We will begin this chapter by learning the basics of real-time interaction in client-side applications. We will use the HDI Explorer application from Chapter 8, Data-driven Applications, a service that provides the necessary backend to implement real-time applications.

We will then implement the server-side application using Node, Twit, and Socket...