Most cityscapes on Google Earth are flat -- simple satellite photographs in two-dimensional space. In a few cases, like New York or San Francisco, a user can soar through a forest of blocky white skyscrapers with no detail on the facades; only major landmarks like the Golden Gate Bridge have been filled in. But soon -- in the next few days or weeks -- downtown Hamburg will take a bow as Google's first viable three-dimensional city.
"With the textured facades, Hamburg is the first city worldwide that can be seen in such detail," Google spokesman Stefan Keuchel said in Hamburg on Wednesday, without mentioning exactly when hundreds of buildings in Hamburg's downtown were due to go live in 3D.
The choice of Hamburg wasn't due to its magnificent architecture so much as the efforts of Hamburg@work, a joint initiative of the city and private business. The group approached Google with the idea -- and an offer to foot the bill -- and the Internet giant, Keuchel said, leapt at the chance.
Expanding its mapping service into the third dimension is high priority for Google. "We want to develop the ultimate virtual globe," said Keuchel. The California-based company plans to build virtual 3D maps of most major cities -- along with a search function that will show, say, every restaurant along a given street.
The problem is that to build a database of a city in 3D, Google needs photographs of every building, from every angle. It plans to collect them with the help of the Internet community. Volunteers can use a program called "Sketch-Up" to fill in the outlines of major buildings with their own photos.
The approach is fundamentally different from Google's main rival, Microsoft, which wants to offer a similar 3D versions of cities on its own mapping service, Virtual Earth. Instead of using uploaded photos from users, though, Microsoft simply bought a company that specializes in gathering such images.
Hamburg ahead of the game
Hamburg administrators provided the dimensions of the downtown buildings as well as a trove of about 1000 aerial pictures of the city taken from an altitude of 500 meters (1,640 feet). Cybercity, a Swiss company specializing in virtual city models, used them to render the building facades, which were then attached to blank 3D objects and exported to Google Earth's special format. Uwe Jens Neumann, the head of Hamburg@work, says "the expenses were minor" and were split between Cybercity and the city.
Hamburg isn't the first city to be rendered in 3D. Cybercity has already created 3D versions of Paris and Florence, and Potsdam-based Remote Sensing Solutions has rendered Berlin, Munich and other German cities in 3D. Those cities are for sale on DVD; but Hamburg will be the first metropolis available to anyone who has downloaded Google Earth's free software.