I mapped my run online with Ordnance Survey today and it said my route was 5.1km. However, my pedometer says it's a distance of 4k. My husband says the OS will be more accurate (especially as I haven't set the pedometer to my pace yet) but I'm not convinced. I really want him to be right though as then it means I'm doing 5.1km in 30mins. Anyone use / trust it at all?