"Flight Unlimited"s terrain graphics were created with stereophotogrammetry. The team gathered aerial photographs from locations in France and the United States. They combined two to three images of each area to create digital reproductions roughly in size. Each location in the game was based on two stereoscopic sets of photographs, which were processed for more than 72 hours by a "dedicated Pentium tucked away in a dark corner". From the contrasting images, the computer generated a terrain "data blanket" with 3D height variations. While the team had considered using satellite or surveillance aircraft images to create the game's terrain graphics, they found that the resolution was inadequate. Material from geographic information systems was also studied, but associate producer Paul Schaffer said that it would have been "astronomically expensive" to obtain data with the necessary resolution.