Carn mor Dearg Arête

[John Wheelhouse]

My son and I drove up from Leeds early afternoon on Friday 1 September with the intention to climb the 'Ben' by the CMD Arete on Saturday. Weather was fine and we set off from the North Face car park at 8.30am. Having looked previously at the Walk Highlands website we were intent on doing the stated 11 miles, but with the intention of making a little better progress on the time of ten hours (I have done it previously). We enjoyed the superb views and my son found the scrambling very enjoyable. We met the usual masses on top and had to navigate round a sea of fell runners who were taking part in the annual Ben Nevis run. We came down the tourist track and followed this to Lochan Meall an t'Suidhe, at the Head of the lochan we proceeded to follow the stream down to the forest to pick up the track down to the North Face Car Park. We arrived back at the car at 4.40pm, knackered but satisfied we had done the hard route. The aspect of the walk I was most surprised about, particularly when we arrived back at the car, was my son had had his GPS tracker on his phone switched on for the whole journey and it registered 14.1 miles travelled. This is quite an anomaly on the route details I downloaded from the Walk Highlands site, so I would appreciate any similar experiences in distance variations. My son wasn't happy about the extra mileage but it hasn't put him off walking - we're planning the next biggie!

[Mal Grey]

Sounds like a great day out with your lad. Its a fantastic route, especially the views of the north face. However, its one hell of a long grassy slope to the ridge on CMD!!!

A rough and ready trace of the route on the map planner suggests 11 miles is right, so it might be your son's GPS thing that hasn't tracked properly. Did it also include mileage done by pottering about before or after the walk?

[Lanky1963]

Did this many years ago, camping at Glen Nevis, so walked up the tourist track to the loch (with a temperature inversion up the Glen to the Mamores) and then down into the valley and up to Carn Dearg Meadhonach and then along the ridge. Had lunch at the top of Carn More Dearg which managed to psych out my good lady looking at the ridge so she went on the path just below the ridge whilst I enjoyed myself along the main ridge.

The top was clear that day, apparently on average there are only 30 clear days a year so thought we were very lucky!

Had a snifter of port at the top to celebrate, then fought the hordes on the way down. We were a few days before the hill race that year as there were some practice runners around. I remember thinking how much their knees were going to hurt in later years, little did I know.....!

Glad you enjoyed the day out, I would always recommend this way up The Ben.

[Skyelines]

A rough and ready trace of the route on the map planner suggests 11 miles is right, so it might be your son's GPS thing that hasn't tracked properly. Did it also include mileage done by pottering about before or after the walk?

A map trace only gives horizontal distance ( 2 dimensions), going up and down adds to the length actually traversed.

GPS calculates distance between each reference point recorded, i.e. in three dimensions.

Think triangles, the hypotenuse is always longer than the base.

[Skyelines]

Just to add a bit to my previous...

The accuracy of the GPS depends on it's error in position recording and how it calculates the distance travelled.
I have found mine telling me I have travelled a distance while remaining stationary.

Just did a little experiment - started the GPS and left it on my desk. In the first couple of minutes it has recorded that it has travelled 0.83km and at 23kph and then settled down.
Of course cumulative positioning errors while moving could add more distance too.

On loch paddling trips the odometer always gives a higher reading for distance than the track does when downloaded onto mapping software. So although the whole trip has been horizontal accumulated errors have added distance and I assume possibly vertical errors too.

[Mal Grey]

A rough and ready trace of the route on the map planner suggests 11 miles is right, so it might be your son's GPS thing that hasn't tracked properly. Did it also include mileage done by pottering about before or after the walk?

A map trace only gives horizontal distance ( 2 dimensions), going up and down adds to the length actually traversed.

GPS calculates distance between each reference point recorded, i.e. in three dimensions.

Think triangles, the hypotenuse is always longer than the base.

Supposedly this takes that into account, though how accurately I wouldn't know.

[Mal Grey]

A rough and ready trace of the route on the map planner suggests 11 miles is right, so it might be your son's GPS thing that hasn't tracked properly. Did it also include mileage done by pottering about before or after the walk?

A map trace only gives horizontal distance ( 2 dimensions), going up and down adds to the length actually traversed.

GPS calculates distance between each reference point recorded, i.e. in three dimensions.

Think triangles, the hypotenuse is always longer than the base.

You're absolutely right, having checked section of known length along grid lines, across a hilly bit, the length was still the same despite the hills. Same on Walkhighland map.