This document describes the data file formats used by the WorldWide Telescope. The files are XML files, and have the extension .WTML. Also covered are a few URL based controls that enable the sharing of single images without creating data files.
Data files are used to add to the default data and user experience of WorldWide Telescope. Data files are used to add single or multiple images -- either foreground images (typically single images referred to as studies) or background images (typically created from a large number of images, covering all or most of the sky, and referred to as surveys), to add tours (animated slide-shows), to create sign up files for communities (public or private groups that can share data), and to add simple or complex sets of data and links for those communities.