[thomersch_]

Satellite/Areal imagery is not the most accurate thing. It might be skewed, misaligned or stitched incorrectly.

In OpenStreetMap areal imagery is a great help, but not the single source of truth. For mappers those images are a good starting point, but there are always other objects near it that can be used as a reference, so that new objects are placed relatively to it.

One single GPS trace is not very meaningful, but if you take several of them into account - optimally from different users with different devices - outliers become more visible and a smoothened path can be derived from it.

OpenStreetMap has a theoretical resolution of a centimeter, but in reality such a precision is not necessary as the devices that are used for consuming maps have a limited accuracy. So if the path is -/+ 5 m, that's fine for us.