Altitude. The elevation of an object from a known level or datum. A measured or computed value that consists of the value and attributes that define the precision of the value, the units of the value, and the encoding of the value. SITEFILE_##.alt_va SITEFILE_##.alt_meth_cd SITEFILE_##.alt_datum_va The accuracy of the elevation in terms of the possible error in feet. An accuracy of +/- 0.1 foot would be entered as ".1".