Podwalk app triggered by GPS coordinates

We are doing a podwalk in Copenhagen. It consists of several chapters (around 14) which corresponds to coordinates on a Google Map. 1. We want to have an iOS app that plays back the audio files when the user is in a certain radius of the corresponding GPS coordinates ex. chapter 3 plays when the user is in a 10 meter radius of coordinate : 55.696744,12.502441 2. The chapters should not be playable outside the geofence of 10-20 meters of the corresponding GPS coordinates. 3. The user should be able to stop and start the audiofile. 4. the route shall be on a google map inside the app. 5. The user should be asked to take a picture 4 certain places on the route. These images shall be send to a certain email adress that we define. here we collect the images and put them on a website later. / From: Telefon fra Fortiden (Phone call from the past)