  Millions of network cameras have been deployed worldwide. Real-time data from
many network cameras can offer instant views of multiple locations with
applications in public safety, transportation management, urban planning,
agriculture, forestry, social sciences, atmospheric information, and more. This
paper describes the real-time data available from worldwide network cameras and
potential applications. Second, this paper outlines the CAM2 System available
to users at https://www.cam2project.net/. This information includes strategies
to discover network cameras and create the camera database, user interface, and
computing platforms. Third, this paper describes many opportunities provided by
data from network cameras and challenges to be addressed.
