See it in action here:
http://cmap-intellisol.rhcloud.com/
This is an app to demonstrate clustered rendering of markers on a Google map from a very large JSON user data set. Initially the map displays a marker for each state. On zooming in it shows increasing levels of detail: city and zip. Similarly, on zooming out it shows decreasing level of detail.
The simple API powering this app is implemented using a file based querying system that works with moderately sized data sets, however for better performance a database sytem should be used.
The back end has been implemented in NodeJS.
Source hierarchy:
[Back end]
server.js - web server application
api/index.js - API
[Front end]
app.js - the client side web app
cmap.js - an abstract wrapper over Google maps
Hosted on OpenShift cloud platform: https://openshift.redhat.com/