Soundmap uses the device's geolocation to mix audio during audio walks, and as a suggestion for geolocating recorded audio. The device's own geolocation output is never stored or harvested in any way - it is only used as a temporary suggested position, when relocating audio, and for mixing audio sources during audiowalk.
The app only records audio when the user explicitly presses the rec-button, which will light up in a red color during the entire recording. Audio recorded by the user, will only be available to other users after the user explicitly uploads it to the server.
Without an account, you cannot commit any content to the server, and thus cannot expose any data to others. You can only obtain an account by participating in one of the Soundmap Workshops hosted by the developer. When participating in such a workshop and obtaining an account, usernames are never real full names and all passwords are generated randomly, to minimize the risks associated with a hypothetical data breach.