For Amateur Radio operators who often travel to unknown places. Forgot to check GL reference? Do not worry. If you have iPhone and GPS is working then you can check your location's GL reference very easily. You do not need internet connection. Ideal if you go to mobile or portable operation often and not sure where GL boundaries are. App shows you 10 digit locator. If you need only 4 or 6 digit, just use first 4 digit or 6 digit, respectively. Note: Usually Grid Locator is 6 digit as defined in ARRL document. This 10 digit is expansion of 6 digit as 7th and 8th are divided by 10 ("0" through "9") then 9th and 10th are divided by 24 ("a" through "x"). This logic is based on article on Wikipedia.