No, not a map with a bad temper or a crocodile in Loch Ness, but a somewhat startling experience with OS digital mapping.

I've subscribed for a couple of years now. £20 a year for permanently updated maps, the same mapping functions as I had with Memory Map and unlimited printing seemed like a good deal. But, as I was wending my way through the Loch Lomond and Trossachs NP yesterday (finishing the route, not venturing out into the hills in that wind and sleet) I discovered a snap-to-map function that I thought was fantastic. Instead of having to plot lots of points so it gave accurate distances and heights, I could just put a couple of points in and it did the wiggles for me. Only in NPs, which is why I hadn't come across it before. Helped me do it much quicker.

Then I looked at the height gained figures: over 1500m from Inversnaid Bunkhouse to E end Loch Katrine. Now, I know there's a bit of a pull up to Loch Katrine and no path round a loch escapes having a few ups and downs, but 1500m! That's the same as the 2 Munros and a Corbett day in the Arrochar Alps. Having used Memory Map for 15 years, I'm used to it overestimating if I'm a bit lazy with where I put the points, but I thought this system would make sure it was completely accurate. I redid it, not snapping. 500m. A threefold increase.

That's quite a shock, and would be a problem for inexperienced walkers. Almost makes me want to go back to the days of cotton reels and counting brown lines. Except I'd need a magnifying glass these days. :(

Thanks for that note. I use the OS for route planning as well. All good EXCEPT that you cannot upload the files to a Garmin Inreach device. So you have to accept the stock maps. I now have the OS MAPS and offline maps downloaded with routes downloaded too onto my iPhone. The Inreach for safety And paper map and compass as prime tools. The Inreach also does not support OS grid units so it is back to lay/long basics. Dara Ohuiginn Mallaig TGO starter this year.