When Google first announced the automatically generated 3D imagery, they said it was generated via stereophotogrammetry from aerial imagery. In our recent post about 3D imagery featuring cruise ships, we explained that it involves taking pictures from different angles and using that to automatically generate the 3D structure. The result of this is that moving objects cannot be captured by this technique. To understand the implications, lets have a look at a few examples around Charles de Gaulle Airport near Paris, France.
Above left: A moving aircraft on the runway has no 3D at all. Above right: A stationary aircraft is in 3D.
When the aircraft moved during image capturing, we get ghostly effects.
The technique used for creating the 3D does not handle over hangs at all well, which is one reason for even stationary aircraft not looking very good. It is also very noticeable on bridges, and the way trees tend to look like bushes with vertical sides rather than a trunk with overhanging branches.
This water tower demonstrates the problem with overhangs. Above left: Water tower in Street View. Above right: Water tower in 3D.
The water tower above shows six distinct images were used to create the faces of the tower, and possibly a seventh for the top. Two of the faces have much greener grass, and the towers shadow is in a completely different direction so they were taken at a different time of day, from the other four faces.
We have put all the above locations into a KML file. It also includes a number of other notable locations around the world, demonstrating that for intricate structures, Google often manually improves on the models. This is one reason why certain locations take longer to release than others. Bridges, particularly, seem to get a lot of attention, so cities with a large river and lots of bridges can expect to take longer than others.
For more interesting effects, look at one of the above aircraft in Google Maps Earth View by clicking here then try tilting the view and watch the aircraft disappear. Next, rotate the view and see how the aircraft is only partly there.
Also have a look at this aircraft. Note how the same aircraft is parked there in overhead view and the tilted view, but as you rotate, the baggage trucks are in different locations.
If you do not see the compass and ’tilt’ buttons in Google Maps, then it is most likely that you are in Maps’ Lite mode. You can find the minimum system requirements for seeing 3D in Google Maps here.