Imported centerline, shown exactly. Editing a handle switches to the fitted spline, which can measure corners differently.

Checks

    Measurements

    Click the track to add a handle, drag to move, right-click to delete. S on a handle makes it the start. Shift-drag or middle-drag to pan, scroll to zoom. Tap the track to add a handle, drag to move, long-press to delete. Drag empty space to pan, pinch to zoom.