Читать книгу Ben Nevis and Glen Coe. 100 low, mid, and high level walks онлайн

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A compass is a very useful aid in mist, even if your skills only extend to ‘northwest, southeast’ rather than precision bearings. Magnetic deviation is about 1° west (2016): to convert a map bearing to a compass one, add 1. No magnetic rocks have been found in this area; it’s you that’s wrong, not the compass!

GPS receivers should be set to the British National Grid (known variously as British Grid, Ord Srvy GB, BNG, or OSGB GRB36). GPS readings are normally good within 10m, and I have given 8-digit (10m accuracy) grid references at various tricky points, such as where you turn down off a ridge. I have recorded these on the hill, checking for plausibility against a 1:25,000 map afterwards. I have found GPS less reliable on steep slopes, such as the corries of Bidean, with a smaller sky in sight, and poor in the Nevis Gorge; such readings should be regarded with some caution. Somewhere on the gadget, if you press the correct buttons, you can find the degree of inaccuracy. The GPS readings are supplementary; this book is designed to be used without a GPS.