While the use of a barometric altimeter setting that provides a zero reading on the ground of the airport is a reference available to pilots, in commercial aviation it is a country-specific procedure that is not often used (it is used, e.g., in Russia, and a few other countries[which?]). Most countries (Far East, North and South America, all of Europe, Africa, Australia) use the airport's AMSL (above mean sea level) elevation as a reference. During approaches to landing, there are several other references that are used, including AFE (above field elevation) which is height referencing the highest point on the airfield, TDZE (touchdown zone elevation) or TH (threshold height) which both refer to the elevation of the landing end of the runway measured AMSL and AGL respectively.