World geodetic systems represent vertical height on the earth’s surface as a height above the ellipsoid. As a global reference the ellipsoid performs well and is used by some drone manufacturers as the default vertical reference system.
Geoid based reference systems are more localized and better represent the earth’s surface locally. In the United States surveyors, engineers and other consumers of mapping products are accustomed to using geoid models for elevations.
There are established tools to modify ellipsoid elevations to geoid elevations. NOAA and NGS provide one such site online at <a href="www.ngs.noaa.gov/geoid">www.ngs.noaa.gov/geoid</a>. Drone pilots capturing data, with say a Sensefly eBee Plus or ‘X’, need to convert the elevations from those flights to geoid based elevations, like GEOID 12B for example.
This session will begin with a brief introductory summary of the ellipsoid and geoid vertical coordinate systems. Then the instructor will compare two different approaches for modifying post flight exif elevations captured in ellipsoid height to the relevant geoid height.