Afternoon all, I do apologise if this has been mentioned on the forum beforehand, I did look but couldn't see anything. I've heard rumours of an error calculating ascents on OS maps online (premium version) but had never noticed it before today. Plotting a route across Dartmoor (when I should be working) I noticed that over a distance of 6.69 KM OS charted an ascent of 17 km. The estimated timing for the route was therefore given at 3h 16mins. The attached image shows a contour line by Top Tor reading 400 metres and the OS route marker showing 985.30 metres. I thought this might be of interest to those who use OS maps online and, like me, had not yet spotted the error and, perhaps like me, thought that they were just super fast walkers instead.