Even if main focus of the app is on measuring lengths and areas, still there are some place where general units might be used. This is a map scale, for instance.
Here you can pick between 3 main systems of measurement:
- Metric. The one that uses meters and kilometers for distance/length by default.
- Imperial. Uses feet and miles by default.
- Nautical. Uses feet and miles by default.
Here is the screen itself: