True altitude, defined as the height above mean sea level (MSL), is crucial for pilots to maintain situational awareness, interpret geographical elevations, and safely avoid obstacles. It is primarily ...

Representing the direction of a line with bearings is a long-standing tradition that continues today on plats, legal descriptions, site plans, and other documents. Calculating the direction of a line ...

The altitude and azimuth instruments made by Edward Troughton in London from the 1790s were remarkably stable and accurate, and Troughton & Simms continued this tradition. Indeed, Frederick W. Simms ...