Line of Position Navigation: Sumner and Saint-Hilaire, The Two Pillars of Modern Celestial Navigation

This book is a unique, concise resource for the history of the development of Line of Position navigation techniques from their invention in the 1840's to the end of the twentieth century. The point of crossing of two or three Lines of Position plotted on a chart quickly and accurately gives a fix of the navigator's position. We owe two nineteenth century navigators for the creation of the basic concepts of celestial navigation we still use today with modern GPS technology: Thomas H. Sumner...