The navigator has from earliest days depended upon measurements of the altitude of heavenly bodies. At first the latitude alone was calculated, then, with the improvement in time-keepers, the longitude also could be obtained. The latitude was for so long a time all that could be determined that it got to have a peculiar value to navigators, and even after it became possible to obtain the longitude, it was supposed to be more dependable than the longitude though the latitude were itself obtained by methods depending upon time, as the reduction to the meridian and single altitude at a given time. In recent editions of Bow- ditch it is advised that the computed point on the line of position be disregarded in favor of one depending on the dead reckoning latitude, though the computed point is nearer the dead reckoning position than the one recommended and is in a popular sense the “most probable” position. So since the navigator has so long depended upon the measurement of the altitude, he has ignored the possibility of obtaining his position by any other measurement.
Line of Position by Azimuth Observations
By A. B. Clements