Startup Idea : Trip planner based on current location and time

If you arrive in a new place for a single day journey or city break, your time frame is very limited. In the same time you will want to visit as much as possible. My idea is an application that will see your current location (based on GPS, for example you will start from the hotel) and you will select a time frame you allocate for the trip. If I select for example 3h, the application will calculate what attractions I can see from my proximity during this time. There will be room for a lot of expansion (like making a top based on a public poll for attractions, setting a different destination at the end of the trip etc.)