Aluskartta is a free Android app developed by maanpuolustus.net that allows users to track AIS (Automatic Identification System) real-time data on a map base provided by the Finnish Transport Agency. The app automatically updates the location and ship information on the map, displaying different types of vessels with color-coded markers. Additionally, nearby vessels are grouped together to streamline performance.

The app provides more information about the vessel by clicking on its name. It's important to note that the AIS data used in the app is licensed under Creative Commons 4.0 by the Traffic Bureau and is not intended for navigation use. It does not meet the requirements of the official chart chart.

Overall, Aluskartta is a great app for those interested in tracking real-time AIS data in Finland. It's easy to use and provides valuable information for anyone interested in vessel tracking.