I’d like to take this opportunity to introduce you to a new project I’ve been working on to showcase enterprise-class data visualization in HTML-based applications. The US Census Browser is an open source application for browsing data from the 2010 US Census.
The app is completely written using HTML and JavaScript, even for the charting/data visualization components. You can check it out in several application ecosystems today:
Apple iTunes: http://itunes.apple.com/us/app/census-browser/id483201717
Google Android: https://market.android.com/details?id=com.tricedesigns.CensusBrowser
BlackBerry App World: http://appworld.blackberry.com/webstore/content/69236?lang=en
Amazon App Store: http://www.amazon.com/Andrew-Trice-US-Census-Browser/dp/B006JDATOY/ref=sr_1_1?ie=UTF8&s=mobile-apps&qid=1323874245&sr=1-1 (this includes support for Kindle Fire)
Support for additional platforms is planned for future development. Future targets include BlackBerry Playbook as well as Android 2.x devices, including the Amazon Kindle Fire and Barnes & Noble Nook Color – Android 2.x does not support SVG graphics in-browser, so I am working on some alternative features.
Update: Kindle Fire and Playbook have been approved, and are now supported. See links above.
You can also view the US Census Browser application in your desktop or mobile browser at: http://tricedesigns.com/census/
Please keep in mind that this application was designed for mobile devices. Internet Explorer in particular does not work well with the Census Browser – use at your own risk. The browser-based application has been tested and works properly in the latest versions of Chrome, Safari, Firefox, and Opera. The US Census Browser application also does not work in Android 2.x and below, due to the fact that these versions of Android do not support SVG graphics in the mobile browser.
Full application source code for the HTML/JS interface and ColdFusion backend system are available at https://github.com/triceam/US-Census-Browser under the terms of the “Modified BSD License”. Be sure to review the README if you want to get this running on your own.
APPLICATION OVERVIEW
The application is essentially a single-page web site, which asynchronously loads data from the backend upon request, and displays that data to the user. The main application file is index.html, which loads the UI and appropriate client-side scripts. The main presentation logic is applied via CSS stylesheets, and the application control is handled by the ApplicationController class, inside of application.js. The ApplicationController class handles state changes within the application and updates the UI accordingly. The main data visualization and data formatting logic is all contained within the censusVisualizer class, which the ApplicationController class uses to render content. All DOM manipulation, event handling, and AJAX requests are performed using jQuery.
The data visualization is implemented 100% client-side, using the Highcharts JavaScript library. Highcharts renders vector graphics client-side, based upon the data that is passed into it. Check out the examples at: http://www.highcharts.com/demo/ for a sample of what it is capable of.
The fluid scrolling and swiping between views is implemented using the iScroll JavaScript library. Note: I’m using iScroll-lite.js. This is a great resource for any HTML-mobile, or mobile-web applications.
PHONEGAP USAGE
The client-side runtime does not have any dependencies for access to device-specific functionality. However, PhoneGap is being used as an application container so that the application can be distributed through various mobile “app stores”.
SERVER-SIDE
The back-end of this application is written using ColdFusion. Yep, that’s right. I used CF. In fact, the server side is ridiculously simple. It is only a single ColdFusion Component (CFC), with three remotely exposed methods for accessing data, and relies upon CF’s built in functionality to serialize JSON. CF is incredibly powerful, and made this project very simple and quick to develop.
Feel free to check it out on github: https://github.com/triceam/US-Census-Browser
You can also check out more technical details at: http://www.tricedesigns.com/2010-census/