| Name | Data Type | Definition | |
|---|---|---|---|
| SFC | string | The distance measured from the surface of the Earth (equivalent to AGL - Above Ground Level). | |
| MSL | string | The distance measured from mean sea level (equivalent to altitude). | |
| W84 | string | The distance measured from the WGS84 ellipsoid. | |
| STD | string | The vertical distance is measured with an altimeter set to the standard atmosphere. | |
| OTHER | string | Other. |