My father retired earlier this year and he bought a High Powered metal detector. This thing will search the ground up to ten miles away. Basically it finds something and points you in a direction to what it has located. Then you move the detector and repeat the process. This thing is amazing the suggested test for the machine is to locate the gold and silver in your local bank vault. So what my father needs is a tablet with gps that does not require data or cell signal and a mapping app for marking the locations and trangulation. Has anybody heard of anything or any app that would do this and what would be the best tablet for the gps locations. Thanks in advance.