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FFF

fall line - A line connecting the waterfalls of nearly parallel rivers that marks a drop in land level.

Federal Geographic Data Committee - See FGDC.

FDGC - Federal Geographic Data Committee - An agency established by the United States Federal Office of Management and Budget responsible for the coordination of development, use, sharing, and dissemination of surveying, mapping, and related spatial data.

fjord - (also fiord) - A long, narrow inlet of the sea between steep slopes.

flume - A narrow gorge, especially one with a stream.

fluxgate compass - An electronic device used to measure magnetic direction.

ford - A shallow place in a body of water, such as a river, where one can cross on foot, by riding an animal, or in a vehicle.

form factor - A term used to describe the way a device is constructed, such as its shape. For example, GPS receivers come in many form factors, such as handheld, PDA, automotive, USB, etc.