|
Plotting of compass bearings.—This is merely the reverse of determining the bearings from a map. With a compass centered over the point on the map from which the bearing was taken, and with the map properly oriented, a line can be projected through the graduation on the compass which corresponds to the bearing. The point to which the bearing is taken will be on that line if the reading and plotting are accurate. If one is using his own bearings, it will be simpler to keep them all magnetic to avoid conversion errors. Use of a compass in storm.—A storm provides the vital justification for carrying a compass at all times in ski mountaineering, for visibility in storm is greatly reduced. One must rely upon the accuracy of the compass, taking care to eliminate local magnetic influence. If such influence is suspected, several readings on a distant object should be taken on a straight course at intervals of about 400 yards. If uniform, the readings will eliminate the possibility of local attraction. One's sense of direction may, under stress, sometimes be completely off—as much as 180°. To avoid this, mark the compass case to show which end of the needle is north. |
|||
|
