AOPA	Aircraft Owners and Pilots Association
SIFT	Scale-Invariant Feature Transform
GLOH	Gradient Location and Orientation Histogram
SURF	Speeded Up Robust Features
LESH	Local Energy-based Shape Histogram
HS	Histogram Spread
ft	Feet
NM	Nautical Mile
FSSRS	Fixed Step Size Random Search
AGL	Above Ground Level
CAVOK	Ceiling and Visibility OK