In 1959 the international yard and pound agreement (between the United States and countries of the Commonwealth of Nations) defined a yard as being exactly 0.9144 metres, which in turn defined the foot as being exactly 0.3048 metres (304.8 mm).
Nautical miles measure distance. 1 nautical mile is the angular distance of 1 minute of arc on the earth's surface. As these differ slightly (6108' at pole c.f. 6046' at equator) 6080 was adopted (this being it's approximate value in the English Channel). The International nautical mile is 1852 metres, so is very slightly different from the UK nautical mile.