Take browsers to the limit: Google

This advice came from the lead engineer of the Google Maps project, Lars Rasmussen.

Speaking at a conference on Web engineering in Sydney, Rasmussen said Maps' use of the XSL+ (Extensible Stylesheet Language) standard and Microsoft's Vector Markup Language as examples of useful technologies seldom used by Web developers. Both are only supported by certain browsers.

If a Web application takes advantage of the best technologies a user's browser can offer, then "each individual gets the 'sexiest' experience in their browser", he said.

"Go beyond browsers' lowest common denominator," he advised developers.

For example, Maps can command Internet Explorer to use VML to display a blue line between geographical points, but use a PNG graphic format and a linear description for the Firefox browser.

The Sydney-based developer revealed the release of Maps created a critical mass of interest from the programming community in the development of AJAX (Asynchronous JavaScript and XML) applications, or Web applications with sophisticated graphics.

Rasmussen said when browser makers saw companies with huge user bases like Google actually using next-generation technology like VML, they became much more enthusiastic about including such innovations in their browsers. An example of this was the upcoming Scalable Vector Graphics support in Firefox, he added.

"Google Maps was originally a C++ app intended to be downloaded separately," he recalled, going back to the days before his startup company, Where 2 Technologies, was acquired by Google last October.

However, that changed when Rasmussen and his colleagues -- looking for some venture capital -- pitched their mapping expertise to Google.

At that point, the team changed their development model and started focusing on the Web instead. "We were surprised by the things you could do in a Web browser," he said.

Firstly, the Web allows rapid deployment and there is no software for users to install. It's also much easier to make sure code runs on multiple browsers compared with multiple operating systems like Mac OS X and Windows.

The downside is that browsers don't give programmers full access to a computer's resources such as memory, process power and hard disk space. This is a bottleneck the engineer sees being removed in future, although he thinks the simplicity of the current Web browsing experience needs to be maintained.

As such, Rasmussen remains disappointed with Google Earth, which is similar to Maps but utilises three-dimensional modelling and has to be downloaded prior to use. "Much as we have tried, we haven't been able to do this in JavaScript," he said, expressing hope that Google Earth and Maps would eventually be merged into one Web application.

In addition, the company will not shy away from releasing unfinished products to its user base, who in turn provide valuable feedback -- when Maps first launched, it received 5,000 e-mails a day.

Recalling an incident which took place early in his career at Google, Rasmussen said one day he was unexpectedly summoned into a meeting with the company's founders Larry Page and Sergey Brin and other executives.

"I was preparing my defence," he said, for fear the immaturity of his project would come under fire. Instead, Page told him Maps worked well enough to launch immediately.

Working for Google has other advantages, he said, adding that when a bug that caused Maps to malfunction with the Firefox browser was discovered, "we called up the Firefox [lead engineer] the weekend before launch, and he came around and plugged in his debugging code".

While interest in the Maps project has always been relatively strong, the engineer said it skyrocketed when satellite imagery was added. Web traffic levels increased overnight by a factor of 10-15 times, Rasmussen claimed.

Although life at Google is good, it's not always predictable. The company's Moon mapping service -- which launched on the anniversary of the original moon landing -- turned out to be partly a practical joke on Rasmussen.

"I was getting all these congratulatory e-mails and I didn't know what the heck was going on," he said, noting Moon was developed in the US. One e-mail was from a friend of astronaut Neil Armstrong who apparently appreciated the software.

Ultimately the engineer is extremely enthusiastic about his project, which has in recent times seen a myriad of third-party programmers use its now-public programming interfaces to add external functionality. Even Microsoft's competing Virtual Earth product -- released this week -- was praised by Rasmussen.

"It's quite good," he grudgingly admitted.