Runways are named by a number between 01 and 36, which is one tenth of the magnetic azimuth of the runway's heading: a runway numbered 09 points east (90°), runway 18 is south (180°), etc. As a value rounded to the nearest ten, it does not, of course, change frequently but we offer to remeasure on-site the azimuth orientation which can lead to the renumbering of runways.