Interactive geographic information systems (GIS) and techniques are disclosed that provide users with a greater degree of flexibility, utility, and information. A markup language is provided that facilitates communication between servers and clients of the interactive GIS, which enables a number of GIS features, such as network links (time-based and view-dependent dynamic data layers), ground overlays, screen overlays, placemarks, 3D models, and stylized GIS elements, such as geometry, icons, description balloons, polygons, and labels in the viewer by which the user sees the target area. The markup language is used to describe a virtual camera view of a geographic feature. A compressed file format holds multiple files utilized to display a geographic feature in a single file.