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Those Cryptic Journal Entries

Compass Bearing - Azimuth

he word "azimuth" comes from an Arabic form of a Latin word meaning "way" or "path." In the illustration, "N 49 E" is an azimuth indicating a compass bearing or direction of 49 east of north (or 41 north of east). "S 70 W" indicates a bearing or direction of 70 west of south (or 20 south of west). Lewis and Clark gave their compass bearings in terms of quadrants or quarters of the compass: 90 from north to east, 90 from east to south, 90 from south to west, and 90 from west back to north. Today, azimuths are often stated in terms of 360, the full circle of the compass rather than quadrants. A modern statement of the azimuth of "S 70 W" would be 250; degrees are always counted in a clockwise direction from compass north.

--John Logan Allen

Those Cryptic Journal Entries

From Discovering Lewis & Clark ®, http://www.lewis-clark.org © 1998-2014
by The Lewis and Clark Fort Mandan Foundation, Washburn, North Dakota.
Journal excerpts are from The Journals of the Lewis and Clark Expedition, edited by Gary E. Moulton
13 vols. (Lincoln: University of Nebraska Press, 1983-2001)