Example image of eyePlorer eyePlorer map for 'Foot (length)': English units Imperial units International System of Units Length Prime (symbol) United States customary units Units of measurement Inch Yard Commonwealth of Nations Metre United States Millimetre Parts-per notation ISO 31-1 Apostrophe Minute of arc India State Plane Coordinate System Retriangulation of Great Britain North American Datum U.S. National Geodetic Survey Datum (geodesy) Global Positioning System Survey of India World Geodetic System Mendenhall Order Commonwealth National Physical Laboratory Peter I of Russia Western culture Gudea Lagash Sumer Ancient Greece Egypt Metrologist Roman Empire Foot Plough England Scotland Henry I of England Footwear Barefoot Ruler Surveying 1:72 scale 3344 Peachtree 500 Fifth Avenue