Location Service is a free Android app developed by Martin Haertling that provides GPS coordinates, altitude above sea level, and signal accuracy. The app uses satellite-based GPS, and it works only outside and far from any obstacles. The altitude indication is not very precise based on the system, but it can still give an idea of the height. The app also includes a compass to help users navigate.

The user interface is simple and easy to navigate, with a clear and concise display of information. The app supports two languages, German and English, making it accessible to a wider audience. Overall, Location Service is a useful tool for those who need to know their GPS location and altitude while outdoors.