LengthUnit.UsSurveyFoot Property
Gets the LengthUnit that represents a US survey foot.
Syntax
public static LengthUnit UsSurveyFoot { get; }Property Value
A length unit that represents a US survey foot.
Remarks
One US survey foot is exactly 1200/3937 meters, or 0.3048006096012192... meters, which means that one international foot is exactly 0.999998 US survey feet. The Abbreviation is "ftUS", but sometimes people use the prime symbol instead, or just "ft".
When the international foot was defined in 1959 as a compromise between the US foot and the British foot, the US decided to use the international foot for all purposes – except for surveying and mapping, where the US foot remained under the name "US survey foot". Only a few US states have switched to the international foot:
The US State Plane Coordinate Systems based on the NAD27 datum use the US survey foot.
The US State Plane Coordinate Systems based on some variant of the NAD83 datum have a primary (federal) definition using meters. However, the states are allowed to define their own conversion to feet:
These states have no NAD 83 legislation, or no defined foot conversion: Alabama, Alaska and Missouri.
These states use the international foot with NAD83: Arizona, Michigan, Montana, North Dakota, Oregon and South Carolina.
Utah once used the international foot with NAD83, but changed to the US survey foot.
Other US states use the US survey foot with NAD83.
However, there are plans to deprecate the survey foot after 2022; see NIST, U.S. Survey Foot.
Platforms
Windows, Linux, Android