Spring 2006

Have you heard of AJAX yet? If not, you'd better get ready for it, because it looks like becoming a leading software technology underpinning future generations of Internet application, whether fixed or mobile.

Actually, none of it is new or proprietary, which looks like good news. It stands for Asynchronous JavaScript + XML, and it involves harnessing Javascript and XML to allow Web pages to interact more dynamically than in the past with Web servers.

In particular, it allows Web pages viewed in browser screens to be updated much more quickly and seamlessly than in the past, without the whole page needing to be re-transmitted by the server and redrawn every time it changes.

Its use is gradually spreading, and leading software developers are quickly taking advantage. Typical is Telcontar, which maintains that AJAX applications are rapidly replacing traditional "click-and-wait" applications - especially for Web-based mapping, local search, driving directions and other map-centric applications.

 

According to J Kim Fennell, Telcontar's president and chief executive: "There is an increasing trend to enhance user experience utilising fluid or 'draggable' maps in AJAX and browser-based applications."

The company has therefore launched what it describes as "a comprehensive application programming interface" to allow developers to create and implement mapping solutions more easily. The API is built on the company's Drill Down Server geospatial software platform, and can work either behind the user's in-house a firewall or through the company's hosted Web services capability.

If you want to know more of the technological background, Telcontar has created a new TileGrid element to extend its existing Map Portrayal service. With this, the URL for each tile in a Web-based map tile grid can be retrieved using a single XML query. Each URL is a set of query parameters that allow the tiles to be rendered just in time.

This compares with other Web-based map tiling systems that pre-render, store and cache every tile at every zoom level for the entire geographic coverage.