ESRI's GIS (geographic information systems) mapping software helps you understand and visualize data to make decisions based on the best information and analysis.
Opticks is an expandable remote sensing and imagery analysis software platform that is free and open source. If you've used other commercial tools like: ERDAS IMAGINE, RemoteView, ENVI, or SOCET GXP, then you need to give Opticks a try. Unlike other competing tools, you can add capability to Opticks by creating an extension. Opticks provides the most advanced extension capability of any other remote sensing tool on the market.
E. Valle, H. Qasim, and I. Celino. Proceedings of 1st International Workshop on Pervasive Web Mapping, Geoprocessing and Services (WebMGS 2010), (2010)
J. Owens, M. Yuan, M. Wachowicz, V. Kantabutra, E. Jr., D. Ames, and A. Gangemi. National Endowment for the Humanities Workshop Visualizing the Past: Tools and Techniques for Understanding Historical Processes, University of Richmond, Virginia, USA, volume 188 of Frontiers in Artificial Intelligence and Applications, IOS Press, (2009)