The National Virtual Ocean Data System's Live Access Server (LAS) is a highly configurable Web server designed to provide access to geo-referenced oceanographic data. From this site, users can visualize data with on-the-fly graphics, request custom subsets of variables in a choice of file formats, access background reference material about the data, and compare variables from different locations. Data are organized by dataset, variable, constraint, or output type, as well as by discipline (atmosphere, ocean, surface marine, land surface, topography, bathymetry), source (satellite, surface data, model output, etc.), temporal resolution or serving institution or organization.