as simple as possible, but no simpler: Mapping Google
There've been many posts on Google's maps, but few capture how much radical innovation is involved. This page gives an extensive overview, Jon Udell's post also links to a Slashdot discussion. To the cognoscenti Google Maps and Gmail are signs of a rich world of web applications that few had anticipated. I do wonder what Google will do with their browser project. GBrowser may make Netscape's old Constellation project seem humble.
The resolution and zoom range of the maps comes from their vector nature; they are not the bitmaps we are all to familiar with. We've been waiting 10 years for someone to deliver vector maps to the masses, now we'll never tolerated raster maps again. PDF, Flash and SVG maps have been done before, but not on this scale.
Some posters claim Google is using VML. That's unlikely as Firefox does not support VML. Nor are they using SVG. They appear to be using some internal XML vector representation and doing something called an XSLT transform (magic to me). Unfortunately OS X Safari is missing the XSLT transform capability. It may appear in Tiger.
This is the first application that's made me consider leaving Safari for Firefox. Apple needs to wakeup.