Wikipedia
Areograph is the commercial name of a photographic technology that assembles photographic components into 3-dimensional environments. Anywhere from 100,000 to several million photographs are stitched by software into a navigable scene, akin to those in a first person shooter. The production of such environments is both faster and cheaper than creating a rendered environment of similar size, as well as being more detailed, given that the source of an Areograph environment is a real-world location.
Drawbacks include the fact that the environment is fundamentally static, so must rely on modelled artefacts, as well as limitations to the resolution of individual photographic components.
The technology is currently used in the Casebook series of games.