Since Apple started automatically pushing out Safari to Windows users, nerds everywhere have been metaphorically beating each other up over browser benchmarks, hackability, and anti-aliasing schemes. But regardless of any particular loyalties, it’s a fact that things on the web look (and sometimes act) differently in different browsers.
Web pages are, at some level, just a set of instructions that need to be interpreted by a web browser to make the picture on your screen. Differences in web browsers such as Microsoft Internet Explorer, Mozilla Firefox, Apple Safari, and the various versions of each (and even differences between the same versions on different operating systems) make it hard for web developers to provide a consistent experience to users. Abobe’s Flex is an open source collection of tools that help developers make consistent, rich Internet applications, independent of a person’s choice of browser.
Applications made with the Flex framework run in Flash Player, a common browser plug-in which has been around since the late 1990′s. Flash was initially a popular way to add interactive graphics, animations, or video to websites, but has evolved into a platform for developers to build entire web and desktop applications. Flex includes a standard set of user interface objects (such as buttons, forms, and the usual features that people expect to see on web and desktop applications), and an object-oriented programming model familiar to web developers. Flex makes it easier for a developer to create feature rich applications that operate consistently regardless of the user’s operating system or browser. While there are other similar platforms for web-based user interfaces, such as ExtJS (a JavaScript library we use) and Microsoft’s Silverlight, Flex is an excellent choice for applications that need animation or complex controls that push the bounds of what is possible in a web browser.
The Washingtonpost.Newsweek Interactive’s The Root – Example of a Flex- enabled mapping interface that lets users map their family trees.
Azavea has already used Flex in a couple different scenarios, both in and out of map applications. The “Roots” section of Washingtonpost.Newsweek Interactive’s www.theroot.com uses Flex to display an interactive graphical family tree. While the data is stored in a conventional database and uses a conventional server behind-the-scenes, the interface is implemented in Flash using Flex and Flex-based diagramming tools. The Flex application interacts with the back-end server using web services (check out “What the Heck is a Web Service?”). Azavea’s DecisionTree uses Flex to power the interactive map page, providing enhanced browser interoperability and enhanced graphics, such as overlays with variable transparency that can be adjusted by the user on the fly.
We’re excited by what we’ve been able to do so far with Flex, and are looking forward to the forthcoming release of ESRI’s ArcGIS API for Flex, which brings the visual sparkle of Flex to ArcGIS Server applications.
