Google has not only ‘pushed the envelope‘ with the abilities of Google Maps, but they have given designers something to ponder as well. See, at this moment there is simply no W3C standard defining the proper way to do what Google has done. At this point, I guess it is truly anyones game. But I would like to think that Google will be able to have this as a set standard since it does seem to work quite well in most browsers.

The maps are gorgeously readable, and they fill as much of the screen (or the printed page) as you give them. Scrolling the map works in the most natural way, by dragging the image. The mapping service dovetails with local.google.com, which finds businesses by city or ZIP code. In direction-finding mode, each step along the route offers a link that, when clicked, pops up an enlarged view of the intersection.

What rich and smart client technologies enable this magic? DHTML, JavaScript, CSS, XML, and XSLT.

As is the tradition when Google launches a new service, curious hackers immediately took Google Maps apart to see how the magic was done. The best early analysis came from Joel Webber, who worked out the details of image tiling, dynamic updating, and route plotting  infoworld.com). Among other interesting discoveries, he found that the application uses the browser’s built-in XSLT engine to transform packets of XML received from the server into search results, displayed as HTML.

This explains why Google Maps supports only Internet Explorer or Mozilla-based browsers. The others, notably Safari and Opera (Overview, Articles, Company), lack built-in XSLT processors.

Commenting on Webber’s post, one reader noted that no W3C standard defines this capability. As is the related XMLHttpRequest object, which enables the browser to programmatically fetch XML from the server and parse it, the built-in XSLT processor was a Microsoft (Profile, Products, Articles) innovation that was later copied by Mozilla. Safari and Opera do support XMLHttpRequest, by the way, which is why they can run Google Suggest, the experimental version of Google’s search that dynamically expands partially typed queries into lists of choices.