Editing Aspen Movie Map (section)

==Features==
The Aspen Movie Map enabled the user to take a [[virtual tour]] through the city of [[Aspen, Colorado]] (that is, a form of surrogate travel). It is an early example of a [[hypermedia]] system.

A gyroscopic stabilizer with four [[16 mm film|16mm]] stop-frame film cameras was mounted on top of a car with an encoder that triggered the cameras every ten feet. The distance was measured from an optical sensor attached to the hub of a bicycle wheel dragged behind the vehicle. The cameras were mounted in order to capture front, back, and side views as the car made its way through the city. Filming took place daily between 10 a.m. and 2 p.m. to minimize lighting discrepancies. The car was carefully driven down the center of every street in Aspen to enable registered [[match cut]]s.

The film was assembled into a collection of discontinuous scenes (one segment per view per city block) and then transferred to [[laserdisc]], the analog-video precursor to modern digital optical disc storage technologies such as [[DVD]]s. A database was made that correlated the layout of the video on the disc with the two-dimensional street plan. Thus linked, the user was able to choose an arbitrary path through the city; the only restrictions being the necessity to stay in the center of the street; move ten feet between steps; and view the street from one of the four [[Orthogonality|orthogonal]] views.

The interaction was controlled through a dynamically generated menu overlaid on top of the video image: speed and viewing angle were modified by the selection of the appropriate icon through a touch-screen interface, harbinger of the ubiquitous interactive-video kiosk. Commands were sent from the client process handling the user input and overlay graphics to a server that accessed the database and controlled the laserdisc players. Another interface feature was the ability to touch any building in the current field of view, and, in a manner similar to the [[Image map|ISMAP]] feature of web browsers, jump to a façade of that building. Selected buildings contained additional data: e.g., interior shots, historical images, menus of restaurants, video interviews of city officials, etc., allowing the user to take a virtual tour through those buildings.

[[File:QADAS.jpg|thumb|The facades of buildings were texture-mapped onto 3D models. The same 3D model was used to translate 2D screen coordinates into a database of buildings in order to provide hyperlinks to additional data.]]

In a later implementation, the [[metadata]], which was in large part automatically extracted from the animation database, was encoded as a digital signal in the analog video. The data encoded in each frame contained all the necessary information to enable a full-featured surrogate-travel experience.

Another feature of the system was a navigation map that was overlaid above the horizon in the top of the frame; the map both served to indicate the user's current position in the city (as well as a trace of streets previously explored) and to allow the user to jump to a two-dimensional city map, which allowed for an alternative way of moving through the city. Additional features of the map interface included the ability to jump back and forth between correlated aerial photographic and cartoon renderings with routes and landmarks highlighted; and to zoom in and out à la [[Charles Eames]]'s ''[[Powers of Ten (film)|Powers of Ten]]'' film.

Aspen was filmed in early fall and winter. The user was able to ''[[in situ]]'' change seasons on demand while moving down the street or looking at a façade. A three-dimensional polygonal model of the city was also generated, using the Quick and Dirty Animation System ([[QADAS]]), which featured three-dimensional [[texture mapping|texture-mapping]] of the facades of landmark buildings, using an algorithm designed by [[Paul Heckbert]]. These computer-graphic images, also stored on the laserdisc, were also correlated to the video, enabling the user to view an abstract rendering of the city in real time.