Even an informal understanding of photogrammetric triangulation would lead one to anticipate the general data requirements for GIANT. Measurements of control, pass, and tie points on a frame, supplemented by some indexing information, comprise the image file. The coordinates of the control points that permit the absolute orientation, sometimes referred to as the geo-registration, comprise the control file. Information, however approximate, about the locations of the exposure stations forms the frame file. The frame file can exist in either of two forms and the user is urged to read Section 2.1.2 carefully to understand the special circumstances surrounding the frame file.

GIANT uses other files for its work, and a directory listing of a project will be likely to show more than the three files mentioned so far. These additional files, however, are created under program control and require no formal intervention on the part of the user. In fact, the user is cautioned against modifying the automatically-generated files with a text editor: their modification can--and should--be achieved through appropriate forms of the Graphical User Interface. The image, control and frame files are the minimal subset required for a GIANT project to be recognized by the system. If any of these three are not present, GIANT will not recognize the project.