TerraFly is a Web-enabled system designed to aid in the visualization of spatial and remote sensed imagery. This system allows one to "fly" over the Earth's surface and explore spatial data such as aerial photography, satellite imagery, street maps, and locale information. Internet capability allows the system to access numerous data sets without the installation of any specialized GIS programs. ... Designed for users of all levels and unlike other geographic information systems, TerraFly runs via standard Web browsers, with no need to download software or data prior to visualization. TerraFly can be delivered as a standalone application or a Web-based tool. FIU's technology of streaming incremental tiles to a Java applet allows the user to "fly" even via modem connections. While "flying" over imagery in TerraFly, the user can see various overlays, such as road names, application-relevant points that are hyperlinked to more information, and shaded zones that depict thematic map layers. The user can also view multi-spectral data by assigning bands to the RGB display and by visualizing the application of various algorithms and filters on multiple spectral bands or multiple data sets. The user can thus compare imagery of the same area acquired at different times or different imagery of the same area acquired concurrently and apply advanced visualization algorithms to the data.