Stereophotogrammetry uses cameras mounted on planes that take oblique pictures wich are used both to create 3D models and the texture applied to these models. Stereophotogrammetry is used in several other industries. For example the technology is now commonly used in facial surgery to digitally reproduce the face of a patient.
This is actually the same technology used by Sweden-based C3 Technologies, a civilian spin off of Defense technology provider Saab, that was bought by Apple for $267 million last year (read more here).
Apple is rumored to be launching its own mapping portal for iOS devices next week during its developer conference starting on Monday June 11.
The technology bought by Apple lies particularly in the fast conversion of the raw oblique imagery into cities. C3 Technologies claimed to need only 5 hours of processing to render in 3D the imagery taken in 1 hour of flight (which allows for 100 km2 of coverage for a plane flying at an altitude of 500 m).
In addition C3 had developed web and mobile clients to allow the fast display of its 3D cities.
At the time of its acquisition C3 had contracts with, among others, Nokia and Yell to provide full 3D cities and the company was already flying seven planes around the world to build its coverage.
During its press conference Google said it will have this 3D coverage for cities that together have 300 million inhabitants by the end of the year.
Today Saab continues to supply for military purpose the technology sold to Apple, see below a video explaining how the technology works: