Backpack Map (IMAGE) Johns Hopkins University Caption The red line marks an engineer's path as he uses EMAPS to create a shipboard map without using GPS. The colors show radiation levels on board. Credit Johns Hopkins University Applied Physics Laboratory Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.